MySQL Connector/Python Developer Guide

Abstract

This manual describes how to install and configure MySQL Connector/Python, a self-contained Python driver for communicating with MySQL servers, and how to use it to develop database applications.

For notes detailing the changes in each release of Connector/Python, see MySQL Connector/Python Release Notes.

For legal information, see the Legal Notices.

For help with using MySQL, please visit either the MySQL Forums or MySQL Mailing Lists, where you can discuss your issues with other MySQL users.

For additional documentation on MySQL products, including translations of the documentation into other languages, and downloadable versions in variety of formats, including HTML and PDF formats, see the MySQL Documentation Library.

Licensing information.  This product may include third-party software, used under license. If you are using a Commercial release of MySQL Connector/Python, see this document for licensing information, including licensing information relating to third-party software that may be included in this Commercial release. If you are using a Community release of MySQL Connector/Python, see this document for licensing information, including licensing information relating to third-party software that may be included in this Community release.

Document generated on: 2016-12-15 (revision: 50182)

Preface and Legal Notices

This manual describes how to install, configure, and develop database applications using MySQL Connector/Python, the a self-contained Python driver for communicating with MySQL servers.

Legal Notices

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Chapter 1 Introduction to MySQL Connector/Python

MySQL Connector/Python enables Python programs to access MySQL databases, using an API that is compliant with the Python Database API Specification v2.0 (PEP 249). It is written in pure Python and does not have any dependencies except for the Python Standard Library.

For notes detailing the changes in each release of Connector/Python, see MySQL Connector/Python Release Notes.

MySQL Connector/Python includes support for:

Almost all features provided by MySQL Server up to and including MySQL Server version 5.7.

Converting parameter values back and forth between Python and MySQL data types, for example Python datetime and MySQL DATETIME. You can turn automatic conversion on for convenience, or off for optimal performance.

All MySQL extensions to standard SQL syntax.

Protocol compression, which enables compressing the data stream between the client and server.

Connections using TCP/IP sockets and on Unix using Unix sockets.

Secure TCP/IP connections using SSL.

Self-contained driver. Connector/Python does not require the MySQL client library or any Python modules outside the standard library.

For information about which versions of Python can be used with different versions of MySQL Connector/Python, see Chapter 3, Connector/Python Versions.

Note

Connector/Python does not support the old MySQL Server authentication methods, which means that MySQL versions prior to 4.1 will not work.

Chapter 2 Guidelines for Python Developers

The following guidelines cover aspects of developing MySQL applications that might not be immediately obvious to developers coming from a Python background:

For security, do not hardcode the values needed to connect and log into the database in your main script. Python has the convention of a config.py module, where you can keep such values separate from the rest of your code.

Python scripts often build up and tear down large data structures in memory, up to the limits of available RAM. Because MySQL often deals with data sets that are many times larger than available memory, techniques that optimize storage space and disk I/O are especially important. For example, in MySQL tables, you typically use numeric IDs rather than string-based dictionary keys, so that the key values are compact and have a predictable length. This is especially important for columns that make up the primary key for an InnoDB table, because those column values are duplicated within each secondary index.

Any application that accepts input must expect to handle bad data.

The bad data might be accidental, such as out-of-range values or misformatted strings. The application can use server-side checks such as unique constraints and NOT NULL constraints, to keep the bad data from ever reaching the database. On the client side, use techniques such as exception handlers to report any problems and take corrective action.

The bad data might also be deliberate, representing an “SQL injection” attack. For example, input values might contain quotation marks, semicolons, % and _ wildcard characters and other characters significant in SQL statements. Validate input values to make sure they have only the expected characters. Escape any special characters that could change the intended behavior when substituted into an SQL statement. Never concatenate a user input value into an SQL statement without doing validation and escaping first. Even when accepting input generated by some other program, expect that the other program could also have been compromised and be sending you incorrect or malicious data.

Because the result sets from SQL queries can be very large, use the appropriate method to retrieve items from the result set as you loop through them. fetchone() retrieves a single item, when you know the result set contains a single row. fetchall() retrieves all the items, when you know the result set contains a limited number of rows that can fit comfortably into memory. fetchmany() is the general-purpose method when you cannot predict the size of the result set: you keep calling it and looping through the returned items, until there are no more results to process.

Since Python already has convenient modules such as pickle and cPickle to read and write data structures on disk, data that you choose to store in MySQL instead is likely to have special characteristics:

Too large to all fit in memory at one time. You use SELECT statements to query only the precise items you need, and aggregate functions to perform calculations across multiple items. You configure the innodb_buffer_pool_size option within the MySQL server to dedicate a certain amount of RAM for caching query results.

Too complex to be represented by a single data structure. You divide the data between different SQL tables. You can recombine data from multiple tables by using a join query. You make sure that related data is kept in sync between different tables by setting up foreign key relationships.

Updated frequently, perhaps by multiple users simultaneously. The updates might only affect a small portion of the data, making it wasteful to write the whole structure each time. You use the SQL INSERT, UPDATE, and DELETE statements to update different items concurrently, writing only the changed values to disk. You use InnoDB tables and transactions to keep write operations from conflicting with each other, and to return consistent query results even as the underlying data is being updated.

Using MySQL best practices for performance can help your application to scale without requiring major rewrites and architectural changes. See Optimization for best practices for MySQL performance. It offers guidelines and tips for SQL tuning, database design, and server configuration.

You can avoid reinventing the wheel by learning the MySQL SQL statements for common operations: operators to use in queries, techniques for bulk loading data, and so on. Some statements and clauses are extensions to the basic ones defined by the SQL standard. See Data Manipulation Statements, Data Definition Statements, and SELECT Syntax for the main classes of statements.

Issuing SQL statements from Python typically involves declaring very long, possibly multi-line string literals. Because string literals within the SQL statements could be enclosed by single quotation, double quotation marks, or contain either of those characters, for simplicity you can use Python's triple-quoting mechanism to enclose the entire statement. For example:

'''It doesn't matter if this string contains 'single'
or "double" quotes, as long as there aren't 3 in a
row.'''

You can use either of the ' or " characters for triple-quoting multi-line string literals.

Many of the secrets to a fast, scalable MySQL application involve using the right syntax at the very start of your setup procedure, in the CREATE TABLE statements. For example, Oracle recommends the ENGINE=INNODB clause for most tables, and makes InnoDB the default storage engine in MySQL 5.5 and up. Using InnoDB tables enables transactional behavior that helps scalability of read-write workloads and offers automatic crash recovery. Another recommendation is to declare a numeric primary key for each table, which offers the fastest way to look up values and can act as a pointer to associated values in other tables (a foreign key). Also within the CREATE TABLE statement, using the most compact column data types that meet your application requirements helps performance and scalability because that enables the database server to move less data back and forth between memory and disk.

Chapter 3 Connector/Python Versions

The following table summarizes the available Connector/Python versions. For series that have reached General Availability (GA) status, development releases in the series prior to the GA version are no longer supported.

Table 3.1 Connector/Python Version Reference

Connector/Python Version | MySQL Server Versions | Python Versions | Connector Status
2.2 | 5.7, 5.6, 5.5 | 3.3 and higher, 2.7 | Developer Milestone
2.1 | 5.7, 5.6, 5.5 | 3.3 and higher, 2.7, 2.6 | Recommended version
2.0 | 5.7, 5.6, 5.5 | 3.3 and higher, 2.7, 2.6 | GA, Supported
1.2 | 5.7, 5.6, 5.5 (5.1, 5.0, 4.1) | 3.1 and higher, 2.7, 2.6 | GA, Supported

Note

MySQL server and Python versions within parentheses are known to work with Connector/Python, but are not officially supported. Bugs might not get fixed for those versions.

Note

Connector/Python does not support the old MySQL Server authentication methods, which means that MySQL versions prior to 4.1 will not work.

Chapter 4 Connector/Python Installation

Table of Contents

4.1 Obtaining Connector/Python

4.2 Installing Connector/Python from a Binary Distribution

4.3 Installing Connector/Python from a Source Distribution

4.4 Verifying Your Connector/Python Installation

Connector/Python runs on any platform where Python is installed. Python comes preinstalled on most Unix and Unix-like systems, such as Linux, OS X, and FreeBSD. On Microsoft Windows, a Python installer is available at the Python Download website. If necessary, download and install Python for Windows before attempting to install Connector/Python.

Note

Connector/Python requires python to be in the system's PATH and installation fails if python cannot be located. On Unix and Unix-like systems, python is normally located in a directory included in the default PATH setting. On Windows, if you install Python, either enable Add python.exe to Path during the installation process, or manually add the directory containing python.exe yourself.

For more information about installation and configuration of Python on Windows, see Using Python on Windows in the Python documentation.

Connector/Python implements the MySQL client/server protocol two ways:

As pure Python. This implementation of the protocol does not require any other MySQL client libraries or other components.

As a C Extension that interfaces with the MySQL C client library. This implementation of the protocol is dependent on the client library, but can use the library provided by either MySQL Connector/C or MySQL Server packages (see MySQL C API Implementations). The C Extension is available as of Connector/Python 2.1.1.

Neither implementation of the client/server protocol has any third-party dependencies. However, if you need SSL support, verify that your Python installation has been compiled using the OpenSSL libraries.

Installation of Connector/Python is similar on every platform and follows the standard Python Distribution Utilities or Distutils. Distributions are available in native format for some platforms, such as RPM packages for Linux.

Python terminology regarding distributions:

Built Distribution: A package created in the native packaging format intended for a given platform. It contains both sources and platform-independent bytecode. Connector/Python binary distributions are built distributions.

Source Distribution: A distribution that contains only source files and is generally platform independent.

4.1 Obtaining Connector/Python

Packages are available at the Connector/Python download site. For some packaging formats, there are different packages for different versions of Python; choose the one appropriate for the version of Python installed on your system.

4.2 Installing Connector/Python from a Binary Distribution

Connector/Python installers in native package formats are available for Windows and for Unix and Unix-like systems:

Windows: MSI installer package

Linux: Yum repository for EL6 and EL7 and Fedora 20 and 21; RPM packages for Oracle Linux, Red Hat, and SuSE; Debian packages for Debian and Ubuntu

OS X: Disk image package with PKG installer

You may need root or administrator privileges to perform the installation operation.

As of Connector/Python 2.1.1, binary distributions are available that include a C Extension that interfaces with the MySQL C client library. Some packaging types have a single distribution file that includes the pure-Python Connector/Python code together with the C Extension. (Windows MSI and OS X Disk Image packages fall into this category.) Other packaging types have two related distribution files: One that includes the pure-Python Connector/Python code, and one that includes only the C Extension. For packaging types that have separate distribution files, install both distributions if you want to use the C Extension. The two files have related names, the difference being that the one that contains the C Extension has “cext” in the distribution file name.

Binary distributions that provide the C Extension are either statically linked to MySQL Connector/C or link to an already installed C client library provided by a Connector/C or MySQL Server installation. For those distributions that are not statically linked, you must install Connector/C or MySQL Server if it is not already present on your system. To obtain either product, visit the MySQL download site.

Installing Connector/Python on Microsoft Windows Using an MSI Package

Connector/Python Windows MSI Installers (.msi files) are available from the Connector/Python download site (see Section 4.1, “Obtaining Connector/Python”). Choose an installer appropriate for the version of Python installed on your system. As of Connector/Python 2.1.1, MSI Installers include the C Extension; it need not be installed separately.

To use the MSI Installer, launch it and follow the prompts in the screens it presents to install Connector/Python in the location of your choosing.

Alternatively, to run the installer from the command line, use this command in a console window, where VER and PYVER are the respective Connector/Python and Python version numbers in the installer file name:

shell> msiexec /i mysql-connector-python-VER-pyPYVER.msi

Subsequent executions of Connector/Python using the MSI installer permit you to either repair or remove the existing Connector/Python installation.

Installing Connector/Python on Linux Using the MySQL Yum Repository

For EL6 or EL7-based platforms and Fedora 19 or 20, you can install Connector/Python using the MySQL Yum repository (see Installing Additional MySQL Products and Components with Yum). You must have the MySQL Yum repository on your system's repository list (for details, see Adding the MySQL Yum Repository). To make sure that your Yum repository is up-to-date, use this command:

shell> sudo yum update mysql-community-release

Then install Connector/Python as follows:

shell> sudo yum install mysql-connector-python

Installing Connector/Python on Linux Using an RPM Package

Connector/Python Linux RPM packages (.rpm files) are available from the Connector/Python download site (see Section 4.1, “Obtaining Connector/Python”).

To install a Connector/Python RPM package (denoted here as PACKAGE.rpm), use this command:

shell> rpm -i PACKAGE.rpm

To install the C Extension (available as of Connector/Python 2.1.1), install the corresponding package with “cext” in the package name.

RPM provides a feature to verify the integrity and authenticity of packages before installing them. To learn more, see Verifying Package Integrity Using MD5 Checksums or GnuPG.

Installing Connector/Python on Linux Using a Debian Package

Connector/Python Debian packages (.deb files) are available for Debian or Debian-like Linux systems from the Connector/Python download site (see Section 4.1, “Obtaining Connector/Python”).

To install a Connector/Python Debian package (denoted here as PACKAGE.deb), use this command:

shell> dpkg -i PACKAGE.deb

To install the C Extension (available as of Connector/Python 2.1.1), install the corresponding package with “cext” in the package name.

Installing Connector/Python on OS X Using a Disk Image

Connector/Python OS X disk images (.dmg files) are available from the Connector/Python download site (see Section 4.1, “Obtaining Connector/Python”). As of Connector/Python 2.1.1, OS X disk images include the C Extension; it need not be installed separately.

Download the .dmg file and install Connector/Python by opening it and double clicking the resulting .pkg file.

4.3 Installing Connector/Python from a Source Distribution

Connector/Python source distributions are platform independent and can be used on any platform. Source distributions are packaged in two formats:

Zip archive format (.zip file)

Compressed tar archive format (.tar.gz file)

Either packaging format can be used on any platform, but Zip archives are more commonly used on Windows systems and tar archives on Unix and Unix-like systems.

Prerequisites for Compiling Connector/Python with the C Extension

As of Connector/Python 2.1.1, source distributions include the C Extension that interfaces with the MySQL C client library. You can build the distribution with or without support for this extension. To build Connector/Python with support for the C Extension, you must satisfy the following prerequisites.

Prerequisites for Windows systems:

Correct version of Visual Studio: VS 2009 for Python 2.7, VS 2010 for Python 3.3

Python development files

MySQL Connector/C or MySQL Server installed, including development files

Prerequisites for Unix and Unix-like systems:

A C/C++ compiler, such as gcc

Python development files

MySQL Connector/C or MySQL Server installed, including development files

You must install Connector/C or MySQL Server if it is not already present on your system. To obtain either product, visit the MySQL download site.

For certain platforms, MySQL development files are provided in separate packages. This is true for RPM and Debian packages, for example.

Installing Connector/Python from Source on Microsoft Windows

A Connector/Python Zip archive (.zip file) is available from the Connector/Python download site (see Section 4.1, “Obtaining Connector/Python”).

To install Connector/Python from a Zip archive, download the latest version and follow these steps:

Unpack the Zip archive in the intended installation directory (for example, C:\mysql-connector\) using WinZip or another tool that can read .zip files.

Start a console window and change location to the folder where you unpacked the Zip archive:

shell> cd C:\mysql-connector\

Inside the Connector/Python folder, perform the installation using this command:

shell> python setup.py install

To include the C Extension (available as of Connector/Python 2.1.1), use this command instead:

shell> python setup.py install --with-mysql-capi="path_name"

The argument to --with-mysql-capi is the path to the installation directory of either MySQL Connector/C or MySQL Server.

To see all options and commands supported by setup.py, use this command:

shell> python setup.py --help

Installing Connector/Python from Source on Unix and Unix-Like Systems

For Unix and Unix-like systems such as Linux, Solaris, OS X, and FreeBSD, a Connector/Python tar archive (.tar.gz file) is available from the Connector/Python download site (see Section 4.1, “Obtaining Connector/Python”).

To install Connector/Python from a tar archive, download the latest version (denoted here as VER), and execute these commands:

shell> tar xzf mysql-connector-python-VER.tar.gz
shell> cd mysql-connector-python-VER
shell> sudo python setup.py install

To include the C Extension (available as of Connector/Python 2.1.1), use this command instead:

shell> sudo python setup.py install --with-mysql-capi=value

The argument to --with-mysql-capi is the path to the installation directory of either MySQL Connector/C or MySQL Server, or the path to the mysql_config command.

To see all options and commands supported by setup.py, use this command:

shell> python setup.py --help

4.4 Verifying Your Connector/Python Installation

On Windows, the default Connector/Python installation location is C:\PythonX.Y\Lib\site-packages\, where X.Y is the Python version you used to install the connector.

On Unix-like systems, the default Connector/Python installation location is /prefix/pythonX.Y/site-packages/, where prefix is the location where Python is installed and X.Y is the Python version. See How installation works in the Python manual.

The C Extension is installed as _mysql_connector.so in the site-packages directory, not in the mysql/connector directory.

Depending on your platform, the installation path might differ from the default. If you are not sure where Connector/Python is installed, do the following to determine its location. The output here shows installation locations as might be seen on OS X:

shell> python
>>> from distutils.sysconfig import get_python_lib

>>> print get_python_lib()            # Python v2.x
/Library/Python/2.7/site-packages

>>> print(get_python_lib())           # Python v3.x
/Library/Frameworks/Python.framework/Versions/3.1/lib/python3.1/site-packages

To test that your Connector/Python installation is working and able to connect to MySQL Server, you can run a very simple program where you supply the login credentials and host information required for the connection. For an example, see Section 5.1, “Connecting to MySQL Using Connector/Python”.

Chapter 5 Connector/Python Coding Examples

Table of Contents

5.1 Connecting to MySQL Using Connector/Python

5.2 Creating Tables Using Connector/Python

5.3 Inserting Data Using Connector/Python

5.4 Querying Data Using Connector/Python

These coding examples illustrate how to develop Python applications and scripts which connect to MySQL Server using MySQL Connector/Python.

5.1 Connecting to MySQL Using Connector/Python

The connect() constructor creates a connection to the MySQL server and returns a MySQLConnection object.

The following example shows how to connect to the MySQL server:

import mysql.connector

cnx = mysql.connector.connect(user='scott', password='tiger',
                              host='127.0.0.1',
                              database='employees')
cnx.close()

Section 7.1, “Connector/Python Connection Arguments” describes the permitted connection arguments.

It is also possible to create connection objects using the connection.MySQLConnection() class:

from mysql.connector import (connection)

cnx = connection.MySQLConnection(user='scott', password='tiger',
                                 host='127.0.0.1',
                                 database='employees')
cnx.close()

Both methods, using the connect() constructor, or the class directly, are valid and functionally equal, but using connector() is preferred and is used in most examples in this manual.

To handle connection errors, use the try statement and catch all errors using the errors.Error exception:

import mysql.connector
from mysql.connector import errorcode

try:
  cnx = mysql.connector.connect(user='scott',
                                database='testt')
except mysql.connector.Error as err:
  if err.errno == errorcode.ER_ACCESS_DENIED_ERROR:
    print("Something is wrong with your user name or password")
  elif err.errno == errorcode.ER_BAD_DB_ERROR:
    print("Database does not exist")
  else:
    print(err)
else:
  cnx.close()

If you have lots of connection arguments, it's best to keep them in a dictionary and use the ** operator:

import mysql.connector

config = {
  'user': 'scott',
  'password': 'tiger',
  'host': '127.0.0.1',
  'database': 'employees',
  'raise_on_warnings': True,
}

cnx = mysql.connector.connect(**config)

cnx.close()

Using the Connector/Python C Extension

As of Connector/Python 2.1.1, the use_pure connection argument determines whether to connect using a pure Python interface to MySQL, or a C Extension that uses the MySQL C client library (see Chapter 8, The Connector/Python C Extension). The default is True (use the pure Python implementation). Setting use_pure to False causes the connection to use the C Extension if your Connector/Python installation includes it. The following examples are similar to others shown previously but with the includion of use_pure=False.

Connect by naming arguments in the connect() call:

import mysql.connector

cnx = mysql.connector.connect(user='scott', password='tiger',
                              host='127.0.0.1',
                              database='employees',
                              use_pure=False)
cnx.close()

Connect using an argument dictionary:

import mysql.connector

config = {
  'user': 'scott',
  'password': 'tiger',
  'host': '127.0.0.1',
  'database': 'employees',
  'raise_on_warnings': True,
  'use_pure': False,
}

cnx = mysql.connector.connect(**config)

cnx.close()

It is also possible to use the C Extension directly, by importing the _mysql_connector module rather than the mysql.connector module. For more information, see Section 8.2, “The _mysql_connector C Extension Module”.

5.2 Creating Tables Using Connector/Python

All DDL (Data Definition Language) statements are executed using a handle structure known as a cursor. The following examples show how to create the tables of the Employee Sample Database. You need them for the other examples.

In a MySQL server, tables are very long-lived objects, and are often accessed by multiple applications written in different languages. You might typically work with tables that are already set up, rather than creating them within your own application. Avoid setting up and dropping tables over and over again, as that is an expensive operation. The exception is temporary tables, which can be created and dropped quickly within an application.

from __future__ import print_function

import mysql.connector
from mysql.connector import errorcode

DB_NAME = 'employees'

TABLES = {}
TABLES['employees'] = (
    "CREATE TABLE `employees` ("
    "  `emp_no` int(11) NOT NULL AUTO_INCREMENT,"
    "  `birth_date` date NOT NULL,"
    "  `first_name` varchar(14) NOT NULL,"
    "  `last_name` varchar(16) NOT NULL,"
    "  `gender` enum('M','F') NOT NULL,"
    "  `hire_date` date NOT NULL,"
    "  PRIMARY KEY (`emp_no`)"
    ") ENGINE=InnoDB")

TABLES['departments'] = (
    "CREATE TABLE `departments` ("
    "  `dept_no` char(4) NOT NULL,"
    "  `dept_name` varchar(40) NOT NULL,"
    "  PRIMARY KEY (`dept_no`), UNIQUE KEY `dept_name` (`dept_name`)"
    ") ENGINE=InnoDB")

TABLES['salaries'] = (
    "CREATE TABLE `salaries` ("
    "  `emp_no` int(11) NOT NULL,"
    "  `salary` int(11) NOT NULL,"
    "  `from_date` date NOT NULL,"
    "  `to_date` date NOT NULL,"
    "  PRIMARY KEY (`emp_no`,`from_date`), KEY `emp_no` (`emp_no`),"
    "  CONSTRAINT `salaries_ibfk_1` FOREIGN KEY (`emp_no`) "
    "     REFERENCES `employees` (`emp_no`) ON DELETE CASCADE"
    ") ENGINE=InnoDB")

TABLES['dept_emp'] = (
    "CREATE TABLE `dept_emp` ("
    "  `emp_no` int(11) NOT NULL,"
    "  `dept_no` char(4) NOT NULL,"
    "  `from_date` date NOT NULL,"
    "  `to_date` date NOT NULL,"
    "  PRIMARY KEY (`emp_no`,`dept_no`), KEY `emp_no` (`emp_no`),"
    "  KEY `dept_no` (`dept_no`),"
    "  CONSTRAINT `dept_emp_ibfk_1` FOREIGN KEY (`emp_no`) "
    "     REFERENCES `employees` (`emp_no`) ON DELETE CASCADE,"
    "  CONSTRAINT `dept_emp_ibfk_2` FOREIGN KEY (`dept_no`) "
    "     REFERENCES `departments` (`dept_no`) ON DELETE CASCADE"
    ") ENGINE=InnoDB")

TABLES['dept_manager'] = (
    "  CREATE TABLE `dept_manager` ("
    "  `dept_no` char(4) NOT NULL,"
    "  `emp_no` int(11) NOT NULL,"
    "  `from_date` date NOT NULL,"
    "  `to_date` date NOT NULL,"
    "  PRIMARY KEY (`emp_no`,`dept_no`),"
    "  KEY `emp_no` (`emp_no`),"
    "  KEY `dept_no` (`dept_no`),"
    "  CONSTRAINT `dept_manager_ibfk_1` FOREIGN KEY (`emp_no`) "
    "     REFERENCES `employees` (`emp_no`) ON DELETE CASCADE,"
    "  CONSTRAINT `dept_manager_ibfk_2` FOREIGN KEY (`dept_no`) "
    "     REFERENCES `departments` (`dept_no`) ON DELETE CASCADE"
    ") ENGINE=InnoDB")

TABLES['titles'] = (
    "CREATE TABLE `titles` ("
    "  `emp_no` int(11) NOT NULL,"
    "  `title` varchar(50) NOT NULL,"
    "  `from_date` date NOT NULL,"
    "  `to_date` date DEFAULT NULL,"
    "  PRIMARY KEY (`emp_no`,`title`,`from_date`), KEY `emp_no` (`emp_no`),"
    "  CONSTRAINT `titles_ibfk_1` FOREIGN KEY (`emp_no`)"
    "     REFERENCES `employees` (`emp_no`) ON DELETE CASCADE"
    ") ENGINE=InnoDB")

The preceding code shows how we are storing the CREATE statements in a Python dictionary called TABLES. We also define the database in a global variable called DB_NAME, which enables you to easily use a different schema.

cnx = mysql.connector.connect(user='scott')
cursor = cnx.cursor()

A single MySQL server can manage multiple databases. Typically, you specify the database to switch to when connecting to the MySQL server. This example does not connect to the database upon connection, so that it can make sure the database exists, and create it if not:

def create_database(cursor):
    try:
        cursor.execute(
            "CREATE DATABASE {} DEFAULT CHARACTER SET 'utf8'".format(DB_NAME))
    except mysql.connector.Error as err:
        print("Failed creating database: {}".format(err))
        exit(1)

try:
    cnx.database = DB_NAME
except mysql.connector.Error as err:
    if err.errno == errorcode.ER_BAD_DB_ERROR:
        create_database(cursor)
        cnx.database = DB_NAME
    else:
        print(err)
        exit(1)

We first try to change to a particular database using the database property of the connection object cnx. If there is an error, we examine the error number to check if the database does not exist. If so, we call the create_database function to create it for us.

On any other error, the application exits and displays the error message.

After we successfully create or change to the target database, we create the tables by iterating over the items of the TABLES dictionary:

for name, ddl in TABLES.iteritems():
    try:
        print("Creating table {}: ".format(name), end='')
        cursor.execute(ddl)
    except mysql.connector.Error as err:
        if err.errno == errorcode.ER_TABLE_EXISTS_ERROR:
            print("already exists.")
        else:
            print(err.msg)
    else:
        print("OK")

cursor.close()
cnx.close()

To handle the error when the table already exists, we notify the user that it was already there. Other errors are printed, but we continue creating tables. (The example shows how to handle the “table already exists” condition for illustration purposes. In a real application, we would typically avoid the error condition entirely by using the IF NOT EXISTS clause of the CREATE TABLE statement.)

The output would be something like this:

Creating table employees: already exists.
Creating table salaries: already exists.
Creating table titles: OK
Creating table departments: already exists.
Creating table dept_manager: already exists.
Creating table dept_emp: already exists.

To populate the employees tables, use the dump files of the Employee Sample Database. Note that you only need the data dump files that you will find in an archive named like employees_db-dump-files-1.0.5.tar.bz2. After downloading the dump files, execute the following commands, adding connection options to the mysql commands if necessary:

shell> tar xzf employees_db-dump-files-1.0.5.tar.bz2
shell> cd employees_db
shell> mysql employees < load_employees.dump
shell> mysql employees < load_titles.dump
shell> mysql employees < load_departments.dump
shell> mysql employees < load_salaries.dump
shell> mysql employees < load_dept_emp.dump
shell> mysql employees < load_dept_manager.dump

5.3 Inserting Data Using Connector/Python

Inserting or updating data is also done using the handler structure known as a cursor. When you use a transactional storage engine such as InnoDB (the default in MySQL 5.5 and higher), you must commit the data after a sequence of INSERT, DELETE, and UPDATE statements.

This example shows how to insert new data. The second INSERT depends on the value of the newly created primary key of the first. The example also demonstrates how to use extended formats. The task is to add a new employee starting to work tomorrow with a salary set to 50000.

Note

The following example uses tables created in the example Section 5.2, “Creating Tables Using Connector/Python”. The AUTO_INCREMENT column option for the primary key of the employees table is important to ensure reliable, easily searchable data.

from __future__ import print_function
from datetime import date, datetime, timedelta
import mysql.connector

cnx = mysql.connector.connect(user='scott', database='employees')
cursor = cnx.cursor()

tomorrow = datetime.now().date() + timedelta(days=1)

add_employee = ("INSERT INTO employees "
               "(first_name, last_name, hire_date, gender, birth_date) "
               "VALUES (%s, %s, %s, %s, %s)")
add_salary = ("INSERT INTO salaries "
              "(emp_no, salary, from_date, to_date) "
              "VALUES (%(emp_no)s, %(salary)s, %(from_date)s, %(to_date)s)")

data_employee = ('Geert', 'Vanderkelen', tomorrow, 'M', date(1977, 6, 14))

# Insert new employee
cursor.execute(add_employee, data_employee)
emp_no = cursor.lastrowid

# Insert salary information
data_salary = {
  'emp_no': emp_no,
  'salary': 50000,
  'from_date': tomorrow,
  'to_date': date(9999, 1, 1),
}
cursor.execute(add_salary, data_salary)

# Make sure data is committed to the database
cnx.commit()

cursor.close()
cnx.close()

We first open a connection to the MySQL server and store the connection object in the variable cnx. We then create a new cursor, by default a MySQLCursor object, using the connection's cursor() method.

We could calculate tomorrow by calling a database function, but for clarity we do it in Python using the datetime module.

Both INSERT statements are stored in the variables called add_employee and add_salary. Note that the second INSERT statement uses extended Python format codes.

The information of the new employee is stored in the tuple data_employee. The query to insert the new employee is executed and we retrieve the newly inserted value for the emp_no column (an AUTO_INCREMENT column) using the lastrowid property of the cursor object.

Next, we insert the new salary for the new employee, using the emp_no variable in the dictionary holding the data. This dictionary is passed to the execute() method of the cursor object if an error occurred.

Since by default Connector/Python turns autocommit off, and MySQL 5.5 and higher uses transactional InnoDB tables by default, it is necessary to commit your changes using the connection's commit() method. You could also roll back using the rollback() method.

5.4 Querying Data Using Connector/Python

The following example shows how to query data using a cursor created using the connection's cursor() method. The data returned is formatted and printed on the console.

The task is to select all employees hired in the year 1999 and print their names and hire dates to the console.

import datetime
import mysql.connector

cnx = mysql.connector.connect(user='scott', database='employees')
cursor = cnx.cursor()

query = ("SELECT first_name, last_name, hire_date FROM employees "
         "WHERE hire_date BETWEEN %s AND %s")

hire_start = datetime.date(1999, 1, 1)
hire_end = datetime.date(1999, 12, 31)

cursor.execute(query, (hire_start, hire_end))

for (first_name, last_name, hire_date) in cursor:
  print("{}, {} was hired on {:%d %b %Y}".format(
    last_name, first_name, hire_date))

cursor.close()
cnx.close()

We first open a connection to the MySQL server and store the connection object in the variable cnx. We then create a new cursor, by default a MySQLCursor object, using the connection's cursor() method.

In the preceding example, we store the SELECT statement in the variable query. Note that we are using unquoted %s-markers where dates should have been. Connector/Python converts hire_start and hire_end from Python types to a data type that MySQL understands and adds the required quotes. In this case, it replaces the first %s with '1999-01-01', and the second with '1999-12-31'.

We then execute the operation stored in the query variable using the execute() method. The data used to replace the %s-markers in the query is passed as a tuple: (hire_start, hire_end).

After executing the query, the MySQL server is ready to send the data. The result set could be zero rows, one row, or 100 million rows. Depending on the expected volume, you can use different techniques to process this result set. In this example, we use the cursor object as an iterator. The first column in the row is stored in the variable first_name, the second in last_name, and the third in hire_date.

We print the result, formatting the output using Python's built-in format() function. Note that hire_date was converted automatically by Connector/Python to a Python datetime.date object. This means that we can easily format the date in a more human-readable form.

The output should be something like this:

..
Wilharm, LiMin was hired on 16 Dec 1999
Wielonsky, Lalit was hired on 16 Dec 1999
Kamble, Dannz was hired on 18 Dec 1999
DuBourdieux, Zhongwei was hired on 19 Dec 1999
Fujisawa, Rosita was hired on 20 Dec 1999
..

Chapter 6 Connector/Python Tutorials

Table of Contents

6.1 Tutorial: Raise Employee's Salary Using a Buffered Cursor

These tutorials illustrate how to develop Python applications and scripts that connect to a MySQL database server using MySQL Connector/Python.

6.1 Tutorial: Raise Employee's Salary Using a Buffered Cursor

The following example script gives a long-overdue 15% raise effective tomorrow to all employees who joined in the year 2000 and are still with the company.

To iterate through the selected employees, we use buffered cursors. (A buffered cursor fetches and buffers the rows of a result set after executing a query; see Section 10.6.1, “cursor.MySQLCursorBuffered Class”.) This way, it is unnecessary to fetch the rows in a new variables. Instead, the cursor can be used as an iterator.

Note

This script is an example; there are other ways of doing this simple task.

from __future__ import print_function

from decimal import Decimal
from datetime import datetime, date, timedelta

import mysql.connector

# Connect with the MySQL Server
cnx = mysql.connector.connect(user='scott', database='employees')

# Get two buffered cursors
curA = cnx.cursor(buffered=True)
curB = cnx.cursor(buffered=True)

# Query to get employees who joined in a period defined by two dates
query = (
  "SELECT s.emp_no, salary, from_date, to_date FROM employees AS e "
  "LEFT JOIN salaries AS s USING (emp_no) "
  "WHERE to_date = DATE('9999-01-01')"
  "AND e.hire_date BETWEEN DATE(%s) AND DATE(%s)")

# UPDATE and INSERT statements for the old and new salary
update_old_salary = (
  "UPDATE salaries SET to_date = %s "
  "WHERE emp_no = %s AND from_date = %s")
insert_new_salary = (
  "INSERT INTO salaries (emp_no, from_date, to_date, salary) "
  "VALUES (%s, %s, %s, %s)")

# Select the employees getting a raise
curA.execute(query, (date(2000, 1, 1), date(2000, 12, 31)))

# Iterate through the result of curA
for (emp_no, salary, from_date, to_date) in curA:

  # Update the old and insert the new salary
  new_salary = int(round(salary * Decimal('1.15')))
  curB.execute(update_old_salary, (tomorrow, emp_no, from_date))
  curB.execute(insert_new_salary,
               (emp_no, tomorrow, date(9999, 1, 1,), new_salary))

  # Commit the changes
  cnx.commit()

cnx.close()

Chapter 7 Connector/Python Connection Establishment

Table of Contents

7.1 Connector/Python Connection Arguments

7.2 Connector/Python Option-File Support

Connector/Python provides a connect() call used to establish connections to the MySQL server. The following sections describe the permitted arguments for connect() and describe how to use option files that supply additional arguments.

7.1 Connector/Python Connection Arguments

A connection with the MySQL server can be established using either the mysql.connector.connect() function or the mysql.connector.MySQLConnection() class:

cnx = mysql.connector.connect(user='joe', database='test')
cnx = MySQLConnection(user='joe', database='test')

The following table describes the arguments that can be used to initiate a connection. An asterisk (*) following an argument indicates a synonymous argument name, available only for compatibility with other Python MySQL drivers. Oracle recommends not to use these alternative names.

Table 7.1 Connection Arguments for Connector/Python

Argument Name | Default | Description
user (username*) |  | The user name used to authenticate with the MySQL server.
password (passwd*) |  | The password to authenticate the user with the MySQL server.
database (db*) |  | The database name to use when connecting with the MySQL server.
host | 127.0.0.1 | The host name or IP address of the MySQL server.
port | 3306 | The TCP/IP port of the MySQL server. Must be an integer.
unix_socket |  | The location of the Unix socket file.
auth_plugin |  | Authentication plugin to use. Added in 1.2.1.
use_unicode | True | Whether to use Unicode.
charset | utf8 | Which MySQL character set to use.
collation | utf8_general_ci | Which MySQL collation to use.
autocommit | False | Whether to autocommit transactions.
time_zone |  | Set the time_zone session variable at connection time.
sql_mode |  | Set the sql_mode session variable at connection time.
get_warnings | False | Whether to fetch warnings.
raise_on_warnings | False | Whether to raise an exception on warnings.
connection_timeout (connect_timeout*) |  | Timeout for the TCP and Unix socket connections.
client_flags |  | MySQL client flags.
buffered | False | Whether cursor objects fetch the results immediately after executing queries.
raw | False | Whether MySQL results are returned as is, rather than converted to Python types.
consume_results | False | Whether to automatically read result sets.
ssl_ca |  | File containing the SSL certificate authority.
ssl_cert |  | File containing the SSL certificate file.
ssl_key |  | File containing the SSL key.
ssl_verify_cert | False | When set to True, checks the server certificate against the certificate file specified by the ssl_ca option. Any mismatch causes a ValueError exception.
force_ipv6 | False | When set to True, uses IPv6 when an address resolves to both IPv4 and IPv6. By default, IPv4 is used in such cases.
dsn |  | Not supported (raises NotSupportedError when used).
pool_name |  | Connection pool name. Added in 1.1.1.
pool_size | 5 | Connection pool size. Added in 1.1.1.
pool_reset_session | True | Whether to reset session variables when connection is returned to pool. Added in 1.1.5.
compress | False | Whether to use compressed client/server protocol. Added in 1.1.2.
converter_class |  | Converter class to use. Added in 1.1.2.
fabric |  | MySQL Fabric connection arguments. Added in 1.2.0.
failover |  | Server failover sequence. Added in 1.2.1.
option_files |  | Which option files to read. Added in 2.0.0.
option_groups | ['client', 'connector_python'] | Which groups to read from option files. Added in 2.0.0.
allow_local_infile | True | Whether to enable LOAD DATA LOCAL INFILE. Added in 2.0.0.
use_pure | True | Whether to use pure Python or C Extension. Added in 2.1.1.

MySQL Authentication Options

Authentication with MySQL uses username and password.

Note

MySQL Connector/Python does not support the old, less-secure password protocols of MySQL versions prior to 4.1.

When the database argument is given, the current database is set to the given value. To change the current database later, execute a USE SQL statement or set the database property of the MySQLConnection instance.

By default, Connector/Python tries to connect to a MySQL server running on the local host using TCP/IP. The host argument defaults to IP address 127.0.0.1 and port to 3306. Unix sockets are supported by setting unix_socket. Named pipes on the Windows platform are not supported.

Connector/Python 1.2.1 and up supports authentication plugins found in MySQL 5.6. This includes mysql_clear_password and sha256_password, both of which require an SSL connection. The sha256_password plugin does not work over a non-SSL connection because Connector/Python does not support RSA encryption.

The connect() method supports an auth_plugin argument that can be used to force use of a particular plugin. For example, if the server is configured to use sha256_password by default and you want to connect to an account that authenticates using mysql_native_password, either connect using SSL or specify auth_plugin='mysql_native_password'.

Character Encoding

By default, strings coming from MySQL are returned as Python Unicode literals. To change this behavior, set use_unicode to False. You can change the character setting for the client connection through the charset argument. To change the character set after connecting to MySQL, set the charset property of the MySQLConnection instance. This technique is preferred over using the SET NAMES SQL statement directly. Similar to the charset property, you can set the collation for the current MySQL session.

Transactions

The autocommit value defaults to False, so transactions are not automatically committed. Call the commit() method of the MySQLConnection instance within your application after doing a set of related insert, update, and delete operations. For data consistency and high throughput for write operations, it is best to leave the autocommit configuration option turned off when using InnoDB or other transactional tables.

Time Zones

The time zone can be set per connection using the time_zone argument. This is useful, for example, if the MySQL server is set to UTC and TIMESTAMP values should be returned by MySQL converted to the PST time zone.

SQL Modes

MySQL supports so-called SQL Modes. which change the behavior of the server globally or per connection. For example, to have warnings raised as errors, set sql_mode to TRADITIONAL. For more information, see Server SQL Modes.

Troubleshooting and Error Handling

Warnings generated by queries are fetched automatically when get_warnings is set to True. You can also immediately raise an exception by setting raise_on_warnings to True. Consider using the MySQL sql_mode setting for turning warnings into errors.

To set a timeout value for connections, use connection_timeout.

Enabling and Disabling Features Using Client Flags

MySQL uses client flags to enable or disable features. Using the client_flags argument, you have control of what is set. To find out what flags are available, use the following:

from mysql.connector.constants import ClientFlag
print '\n'.join(ClientFlag.get_full_info())

If client_flags is not specified (that is, it is zero), defaults are used for MySQL 4.1 and higher. If you specify an integer greater than 0, make sure all flags are set properly. A better way to set and unset flags individually is to use a list. For example, to set FOUND_ROWS, but disable the default LONG_FLAG:

flags = [ClientFlag.FOUND_ROWS, -ClientFlag.LONG_FLAG]
mysql.connector.connect(client_flags=flags)

Result Set Handling

By default, MySQL Connector/Python does not buffer or prefetch results. This means that after a query is executed, your program is responsible for fetching the data. This avoids excessive memory use when queries return large result sets. If you know that the result set is small enough to handle all at once, you can fetch the results immediately by setting buffered to True. It is also possible to set this per cursor (see Section 10.2.6, “MySQLConnection.cursor() Method”).

Results generated by queries normally are not read until the client program fetches them. To automatically consume and discard result sets, set the consume_results option to True. The result is that all results are read, which for large result sets can be slow. (In this case, it might be preferable to close and reopen the connection.) This option is available as of Connector/Python 1.1.2.

Type Conversions

By default, MySQL types in result sets are converted automatically to Python types. For example, a DATETIME column value becomes a datetime.datetime object. To disable conversion, set the raw option to True. You might do this to get better performance or perform different types of conversion yourself.

Connecting through SSL

Using SSL connections is possible when your Python installation supports SSL, that is, when it is compiled against the OpenSSL libraries. When you provide the ssl_ca, ssl_key and ssl_cert options, the connection switches to SSL, and the client_flags option includes the ClientFlag.SSL value automatically. You can use this in combination with the compressed option set to True.

As of Connector/Python 2.2.2, if the MySQL server supports SSL connections, Connector/Python attempts to establish a secure (encrypted) connection by default, falling back to an unencrypted connection otherwise.

From Connector/Python 1.2.1 through Connector/Python 2.2.1, it is possible to establish an SSL connection using only the ssl_ca opion. The ssl_key and ssl_cert arguments are optional. However, when either is given, both must be given or an AttributeError is raised.

# Note (Example is valid for Python v2 and v3)
from __future__ import print_function

import sys

#sys.path.insert(0, 'python{0}/'.format(sys.version_info[0]))

import mysql.connector
from mysql.connector.constants import ClientFlag

config = {
    'user': 'ssluser',
    'password': 'asecret',
    'host': '127.0.0.1',
    'client_flags': [ClientFlag.SSL],
    'ssl_ca': '/opt/mysql/ssl/ca.pem',
    'ssl_cert': '/opt/mysql/ssl/client-cert.pem',
    'ssl_key': '/opt/mysql/ssl/client-key.pem',
}

cnx = mysql.connector.connect(**config)
cur = cnx.cursor(buffered=True)
cur.execute("SHOW STATUS LIKE 'Ssl_cipher'")
print(cur.fetchone())
cur.close()
cnx.close()

Connection Pooling

With either the pool_name or pool_size argument present, Connector/Python creates the new pool. If the pool_name argument is not given, the connect() call automatically generates the name, composed from whichever of the host, port, user, and database connection arguments are given, in that order. If the pool_size argument is not given, the default size is 5 connections.

The pool_reset_session permits control over whether session variables are reset when the connection is returned to the pool. The default is to reset them.

Connection pooling is supported as of Connector/Python 1.1.1. See Section 9.1, “Connector/Python Connection Pooling”.

Protocol Compression

The boolean compress argument indicates whether to use the compressed client/server protocol (default False). This provides an easier alternative to setting the ClientFlag.COMPRESS flag. This argument is available as of Connector/Python 1.1.2.

Converter Class

The converter_class argument takes a class and sets it when configuring the connection. An AttributeError is raised if the custom converter class is not a subclass of conversion.MySQLConverterBase. This argument is available as of Connector/Python 1.1.2. Before 1.1.2, setting a custom converter class is possible only after instantiating a new connection object.

The boolean compress argument indicates whether to use the compressed client/server protocol (default False). This provides an easier alternative to setting the ClientFlag.COMPRESS flag. This argument is available as of Connector/Python 1.1.2.

MySQL Fabric Support

To request a MySQL Fabric connection, provide a fabric argument that specifies to contact Fabric. For details, see Requesting a Fabric Connection.

Server Failover

As of Connector/Python 1.2.1, the connect() method accepts a failover argument that provides information to use for server failover in the event of connection failures. The argument value is a tuple or list of dictionaries (tuple is preferred because it is nonmutable). Each dictionary contains connection arguments for a given server in the failover sequence. Permitted dictionary values are: user, password, host, port, unix_socket, database, pool_name, pool_size.

Option File Support

As of Connector/Python 2.0.0, option files are supported using two options for connect():

option_files: Which option files to read. The value can be a file path name (a string) or a sequence of path name strings. By default, Connector/Python reads no option files, so this argument must be given explicitly to cause option files to be read. Files are read in the order specified.

option_groups: Which groups to read from option files, if option files are read. The value can be an option group name (a string) or a sequence of group name strings. If this argument is not given, the default value is ['client', 'connector_python'] to read the [client] and [connector_python] groups.

For more information, see Section 7.2, “Connector/Python Option-File Support”.

LOAD DATA LOCAL INFILE

Prior to Connector/Python 2.0.0, to enable use of LOAD DATA LOCAL INFILE, clients had to explicitly set the ClientFlag.LOCAL_FILES flag. As of 2.0.0, this flag is enabled by default. To disable it, the allow_local_infile connection option can be set to False at connect time (the default is True).

Compatibitility with Other Connection Interfaces

passwd, db and connect_timeout are valid for compatibility with other MySQL interfaces and are respectively the same as password, database and connection_timeout. The latter take precedence. Data source name syntax or dsn is not used; if specified, it raises a NotSupportedError exception.

Client/Server Protocol Implementation

Connector/Python can use a pure Python interface to MySQL, or a C Extension that uses the MySQL C client library. The use_pure connection argument determines which. The default is True (use the pure Python implementation). Setting use_pure to False causes the connection to use the C Extension if your Connector/Python installation includes it.

The use_pure argument is available as of Connector/Python 2.1.1. For more information, see Chapter 8, The Connector/Python C Extension.

7.2 Connector/Python Option-File Support

As of version 2.0.0, Connector/Python has the capability of reading options from option files. (For general information about option files in MySQL, see Using Option Files.) Two arguments for the connect() call control use of option files in Connector/Python programs:

option_files: Which option files to read. The value can be a file path name (a string) or a sequence of path name strings. By default, Connector/Python reads no option files, so this argument must be given explicitly to cause option files to be read. Files are read in the order specified.

option_groups: Which groups to read from option files, if option files are read. The value can be an option group name (a string) or a sequence of group name strings. If this argument is not given, the default value is ['client', 'connector_python'], to read the [client] and [connector_python] groups.

Connector/Python also supports the !include and !includedir inclusion directives within option files. These directives work the same way as for other MySQL programs (see Using Option Files).

This example specifies a single option file as a string:

cnx = mysql.connector.connect(option_files='/etc/mysql/connectors.cnf')

This example specifies multiple option files as a sequence of strings:

mysql_option_files = [
    '/etc/mysql/connectors.cnf',
    './development.cnf',
]
cnx = mysql.connector.connect(option_files=mysql_option_files)

Connector/Python reads no option files by default, for backward compatibility with versions older than 2.0.0. This differs from standard MySQL clients such as mysql or mysqldump, which do read option files by default. To find out which option files the standard clients read on your system, invoke one of them with its --help option and examine the output. For example:

shell> mysql --help
...
Default options are read from the following files in the given order:
/etc/my.cnf /etc/mysql/my.cnf /usr/local/mysql/etc/my.cnf ~/.my.cnf
...

If you specify the option_files connection argument to read option files, Connector/Python reads the [client] and [connector_python] option groups by default. To specify explicitly which groups to read, use the option_groups connection argument. The following example causes only the [connector_python] group to be read:

cnx = mysql.connector.connect(option_files='/etc/mysql/connectors.cnf',
                              option_groups='connector_python')

Other connection arguments specified in the connect() call take precedence over options read from option files. Suppose that /etc/mysql/connectors.conf contains these lines:

[client]
database=cpyapp

The following connect() call includes no database connection argument. The resulting connection uses cpyapp, the database specified in the option file:

cnx = mysql.connector.connect(option_files='/etc/mysql/connectors.cnf')

By contrast, the following connect() call specifies a default database different from the one found in the option file. The resulting connection uses cpyapp_dev as the default database, not cpyapp:

cnx2 = mysql.connector.connect(option_files='/etc/mysql/connectors.cnf',
                               database='cpyapp_dev')

Connector/Python raises a ValueError if an option file cannot be read, or has already been read. This includes files read by inclusion directives.

For the [connector_python] group, only options supported by Connector/Python are accepted. Unrecognized options cause a ValueError to be raised.

For other option groups, Connector/Python ignores unrecognized options.

It is not an error for a named option group not to exist.

Connector/Python treats option values in option files as strings and evaluates them using eval(). This enables specification of option values more complex than simple scalars. For example, the fabric connection option requires a dictionary value, which can be specified like this:

[connector_python]
fabric={'host': 'localhost', 'username': 'webuser', 'password': 'webpass'}

Option values in option files must be specified on a single line, a constraint that does not apply to options specified directly in application code. For example, in an application, this is legal:

conn = mysql.connector.connect(
    fabric={'host': 'localhost',
            'username': 'webuser',
            'password': 'webpass'
            }
    )

In an option file, attempting to use similar multiple-line formatting as shown here produces an error:

[connector_python]
fabric={'host': 'localhost',
        'username': 'webuser',
        'password': 'webpass'
        }

Chapter 8 The Connector/Python C Extension

Table of Contents

8.1 Application Development with the Connector/Python C Extension

8.2 The _mysql_connector C Extension Module

Connector/Python supports (as of version 2.1.1) a C Extension that interfaces with the MySQL C client library. For queries that return large result sets, using the C Extension can improve performance compared to a “pure Python” implementation of the MySQL client/server protocol. Section 8.1, “Application Development with the Connector/Python C Extension”, describes how applications that use the mysql.connector module can use the C Extension. It is also possible to use the C Extension directly, by importing the _mysql_connector module rather than the mysql.connector module. See Section 8.2, “The _mysql_connector C Extension Module”. For information about installing the C Extension, see Chapter 4, Connector/Python Installation.

8.1 Application Development with the Connector/Python C Extension

Installations of Connector/Python from version 2.1.1 on support a use_pure argument to connect() that indicates whether to use the pure Python interface to MySQL or the C Extension that uses the MySQL C client library:

By default, use_pure is True and the C Extension is not used even for Connector/Python installations that include it.

For Connector/Python installations that include the C Extension, enable it by passing a use_pure=False argument to connect().

For Connector/Python installations that do not include the C Extension, passing use_pure=False to connect() raises an exception.

For older Connector/Python installations that know nothing of the C Extension (before version 2.1.1), passing use_pure to connect() raises an exception regardless of its value.

Note

On OS X, if your Connector/Python installation includes the C Extension, but Python scripts are unable to use it, try setting your DYLD_LIBRARY_PATH environment variable the directory containing the C client library. For example:

export DYLD_LIBRARY_PATH=/usr/local/mysql/lib   (for sh)
setenv DYLD_LIBRARY_PATH /usr/local/mysql/lib   (for tcsh)

If you built the C Extension from source, this directory should be the one containing the C client library against which the extension was built.

If you need to check whether your Connector/Python installation is aware of the C Extension, test the HAVE_CEXT value. There are different approaches for this. Suppose that your usual arguments for connect() are specified in a dictionary:

config = {
  'user': 'scott',
  'password': 'tiger',
  'host': '127.0.0.1',
  'database': 'employees',
}

The following example illustrates one way to add use_pure to the connection arguments:

import mysql.connector

if mysql.connector.__version_info__ > (2, 1) and mysql.connector.HAVE_CEXT:
  config['use_pure'] = False

Alternatively, add use_pure to the configuration arguments as follows:

try:
  have_cext = mysql.connector.HAVE_CEXT
except AttributeError:
  have_cext = False

if have_cext:
  config['use_pure'] = False

8.2 The _mysql_connector C Extension Module

To use the C Extension directly, import the _mysql_connector module rather than mysql.connector, then use the _mysql_connector.MySQL() class to obtain a MySQL instance. For example:

import _mysql_connector

ccnx = _mysql_connector.MySQL()
ccnx.connect(user='scott', password='tiger',
             host='127.0.0.1', database='employees')

ccnx.query("SHOW VARIABLES LIKE 'version%'")
row = ccnx.fetch_row()
while row:
  print(row)
  row = ccnx.fetch_row()
ccnx.free_result()

ccnx.close()

For more information, see Chapter 11, Connector/Python C Extension API Reference.

Chapter 9 Connector/Python Other Topics

Table of Contents

9.1 Connector/Python Connection Pooling

9.2 Connector/Python Fabric Support

9.3 Connector/Python Django Backend

This section describes additional Connection/Python features:

Connection pooling: Section 9.1, “Connector/Python Connection Pooling”

Django backend for MySQL: Section 9.3, “Connector/Python Django Backend”

9.1 Connector/Python Connection Pooling

MySQL Connector/Python 1.1.1 and up supports simple connection pooling that has these characteristics:

The mysql.connector.pooling module implements pooling.

A pool opens a number of connections and handles thread safety when providing connections to requesters.

The size of a connection pool is configurable at pool creation time. It cannot be resized thereafter.

A connection pool can be named at pool creation time. If no name is given, one is generated using the connection parameters.

The connection pool name can be retrieved from the connection pool or connections obtained from it.

It is possible to have multiple connection pools. This enables applications to support pools of connections to different MySQL servers, for example.

For each connection request, the pool provides the next available connection. No round-robin or other scheduling algorithm is used. If a pool is exhausted, a PoolError is raised.

It is possible to reconfigure the connection parameters used by a pool. These apply to connections obtained from the pool thereafter. Reconfiguring individual connections obtained from the pool by calling the connection config() method is not supported.

Applications that can benefit from connection-pooling capability include:

Middleware that maintains multiple connections to multiple MySQL servers and requires connections to be readily available.

Web sites that can have more “permanent” connections open to the MySQL server.

A connection pool can be created implicitly or explicitly.

To create a connection pool implicitly: Open a connection and specify one or more pool-related arguments (pool_name, pool_size). For example:

dbconfig = {
  "database": "test",
  "user":     "joe"
}

cnx = mysql.connector.connect(pool_name = "mypool",
                              pool_size = 3,
                              **dbconfig)

The pool name is restricted to alphanumeric characters and the special characters ., _, *, $, and #. The pool name must be no more than pooling.CNX_POOL_MAXNAMESIZE characters long (default 64).

The pool size must be greater than 0 and less than pooling.CNX_POOL_MAXSIZE (default 32).

With either the pool_name or pool_size argument present, Connector/Python creates the new pool. If the pool_name argument is not given, the connect() call automatically generates the name, composed from whichever of the host, port, user, and database connection arguments are given, in that order. If the pool_size argument is not given, the default size is 5 connections.

Subsequent calls to connect() that name the same connection pool return connections from the existing pool. Any pool_size or connection parameter arguments are ignored, so the following connect() calls are equivalent to the original connect() call shown earlier:

cnx = mysql.connector.connect(pool_name = "mypool", pool_size = 3)
cnx = mysql.connector.connect(pool_name = "mypool", **dbconfig)
cnx = mysql.connector.connect(pool_name = "mypool")

Pooled connections obtained by calling connect() with a pool-related argument have a class of PooledMySQLConnection (see Section 10.4, “pooling.PooledMySQLConnection Class”). PooledMySQLConnection pooled connection objects are similar to MySQLConnection unpooled connection objects, with these differences:

To release a pooled connection obtained from a connection pool, invoke its close() method, just as for any unpooled connection. However, for a pooled connection, close() does not actually close the connection but returns it to the pool and makes it available for subsequent connection requests.

A pooled connection cannot be reconfigured using its config() method. Connection changes must be done through the pool object itself, as described shortly.

A pooled connection has a pool_name property that returns the pool name.

To create a connection pool explicitly: Create a MySQLConnectionPool object (see Section 10.3, “pooling.MySQLConnectionPool Class”):

dbconfig = {
  "database": "test",
  "user":     "joe"
}

cnxpool = mysql.connector.pooling.MySQLConnectionPool(pool_name = "mypool",
                                                      pool_size = 3,
                                                      **dbconfig)

To request a connection from the pool, use its get_connection() method:

cnx1 = cnxpool.get_connection()
cnx2 = cnxpool.get_connection()

When you create a connection pool explicitly, it is possible to use the pool object's set_config() method to reconfigure the pool connection parameters:

dbconfig = {
  "database": "performance_schema",
  "user":     "admin",
  "password": "secret"
}

cnxpool.set_config(**dbconfig)

Connections requested from the pool after the configuration change use the new parameters. Connections obtained before the change remain unaffected, but when they are closed (returned to the pool) are reopened with the new parameters before being returned by the pool for subsequent connection requests.

9.2 Connector/Python Fabric Support

MySQL Fabric is a system for managing a farm of MySQL servers (and other components). Fabric provides an extensible and easy to use system for managing a MySQL deployment for sharding and high-availability.

Connector/Python 1.2.0 and up supports Fabric and provides these capabilities:

Requesting a connection to a MySQL server managed by Fabric is as transparent as possible to users already familiar with Connector/Python.

Connector/Python is able to get a MySQL server connection given a high-availability group and a mode specifying whether the connection is read-only or also permits updates (read-write).

Connector/Python supports sharding and is able to find the correct MySQL server for a given table or tables and key based on scope (local or global) and mode (read-only or read-write). RANGE and HASH mechanisms are supported transparently to the user.

Among secondary MySQL servers in the same group, load balancing of read-only operations occurs based on server weight.

Faulty MySQL servers are reported to Fabric, and failover is supported when failure occurs for a server in a group.

Connector/Python caches information coming from Fabric to speed up operations. Failures connecting to a MySQL server reset this cache. The time to live for cached information can be set by Fabric, or a default is used otherwise.

Fabric support applies to versions of Python supported by Connector/Python itself (see Chapter 3, Connector/Python Versions). In particular, you can use Connector/Python with Python 3.1 and higher to establish Fabric connections, even though Fabric does not support Python 3.

For more information, see MySQL Fabric.

9.3 Connector/Python Django Backend

Connector/Python 1.1.1 and up includes a mysql.connector.django module that provides a Django backend for MySQL. This backend supports new features found in MySQL 5.6 such as fractional seconds support for temporal data types.

Django Configuration

Django uses a configuration file named settings.py that contains a variable called DATABASES (see https://docs.djangoproject.com/en/1.5/ref/settings/#std:setting-DATABASES). To configure Django to use Connector/Python as the MySQL backend, the example found in the Django manual can be used as a basis:

DATABASES = {
    'default': {
        'NAME': 'user_data',
        'ENGINE': 'mysql.connector.django',
        'USER': 'mysql_user',
        'PASSWORD': 'priv4te',
        'OPTIONS': {
          'autocommit': True,
        },
    }
}

It is possible to add more connection arguments using OPTIONS.

Support for MySQL Features

Django can launch the MySQL client application mysql. When the Connector/Python backend does this, it arranges for the sql_mode system variable to be set to TRADITIONAL at startup.

Some MySQL features are enabled depending on the server version. For example, support for fractional seconds precision is enabled when connecting to a server from MySQL 5.6.4 or higher. Django's DateTimeField is stored in a MySQL column defined as DATETIME(6), and TimeField is stored as TIME(6). For more information about fractional seconds support, see Fractional Seconds in Time Values.

Chapter 10 Connector/Python API Reference

Table of Contents

10.1 mysql.connector Module

10.1.1 mysql.connector.connect() Method

10.1.2 mysql.connector.apilevel Property

10.1.3 mysql.connector.paramstyle Property

10.1.4 mysql.connector.threadsafety Property

10.1.5 mysql.connector.__version__ Property

10.1.6 mysql.connector.__version_info__ Property

10.2 connection.MySQLConnection Class

10.2.1 connection.MySQLConnection() Constructor

10.2.2 MySQLConnection.close() Method

10.2.3 MySQLConnection.commit() Method

10.2.4 MySQLConnection.config() Method

10.2.5 MySQLConnection.connect() Method

10.2.6 MySQLConnection.cursor() Method

10.2.7 MySQLConnection.cmd_change_user() Method

10.2.8 MySQLConnection.cmd_debug() Method

10.2.9 MySQLConnection.cmd_init_db() Method

10.2.10 MySQLConnection.cmd_ping() Method

10.2.11 MySQLConnection.cmd_process_info() Method

10.2.12 MySQLConnection.cmd_process_kill() Method

10.2.13 MySQLConnection.cmd_query() Method

10.2.14 MySQLConnection.cmd_query_iter() Method

10.2.15 MySQLConnection.cmd_quit() Method

10.2.16 MySQLConnection.cmd_refresh() Method

10.2.17 MySQLConnection.cmd_reset_connection() Method

10.2.18 MySQLConnection.cmd_shutdown() Method

10.2.19 MySQLConnection.cmd_statistics() Method

10.2.20 MySQLConnection.disconnect() Method

10.2.21 MySQLConnection.get_row() Method

10.2.22 MySQLConnection.get_rows() Method

10.2.23 MySQLConnection.get_server_info() Method

10.2.24 MySQLConnection.get_server_version() Method

10.2.25 MySQLConnection.is_connected() Method

10.2.26 MySQLConnection.isset_client_flag() Method

10.2.27 MySQLConnection.ping() Method

10.2.28 MySQLConnection.reconnect() Method

10.2.29 MySQLConnection.reset_session() Method

10.2.30 MySQLConnection.rollback() Method

10.2.31 MySQLConnection.set_charset_collation() Method

10.2.32 MySQLConnection.set_client_flags() Method

10.2.33 MySQLConnection.shutdown() Method

10.2.34 MySQLConnection.start_transaction() Method

10.2.35 MySQLConnection.autocommit Property

10.2.36 MySQLConnection.can_consume_results Property

10.2.37 MySQLConnection.charset Property

10.2.38 MySQLConnection.collation Property

10.2.39 MySQLConnection.connection_id Property

10.2.40 MySQLConnection.database Property

10.2.41 MySQLConnection.get_warnings Property

10.2.42 MySQLConnection.in_transaction Property

10.2.43 MySQLConnection.raise_on_warnings Property

10.2.44 MySQLConnection.server_host Property

10.2.45 MySQLConnection.server_port Property

10.2.46 MySQLConnection.sql_mode Property

10.2.47 MySQLConnection.time_zone Property

10.2.48 MySQLConnection.unix_socket Property

10.2.49 MySQLConnection.user Property

10.3 pooling.MySQLConnectionPool Class

10.3.1 pooling.MySQLConnectionPool Constructor

10.3.2 MySQLConnectionPool.add_connection() Method

10.3.3 MySQLConnectionPool.get_connection() Method

10.3.4 MySQLConnectionPool.set_config() Method

10.3.5 MySQLConnectionPool.pool_name Property

10.4 pooling.PooledMySQLConnection Class

10.4.1 pooling.PooledMySQLConnection Constructor

10.4.2 PooledMySQLConnection.close() Method

10.4.3 PooledMySQLConnection.config() Method

10.4.4 PooledMySQLConnection.pool_name Property

10.5 cursor.MySQLCursor Class

10.5.1 cursor.MySQLCursor Constructor

10.5.2 MySQLCursor.callproc() Method

10.5.3 MySQLCursor.close() Method

10.5.4 MySQLCursor.execute() Method

10.5.5 MySQLCursor.executemany() Method

10.5.6 MySQLCursor.fetchall() Method

10.5.7 MySQLCursor.fetchmany() Method

10.5.8 MySQLCursor.fetchone() Method

10.5.9 MySQLCursor.fetchwarnings() Method

10.5.10 MySQLCursor.stored_results() Method

10.5.11 MySQLCursor.column_names Property

10.5.12 MySQLCursor.description Property

10.5.13 MySQLCursor.lastrowid Property

10.5.14 MySQLCursor.rowcount Property

10.5.15 MySQLCursor.statement Property

10.5.16 MySQLCursor.with_rows Property

10.6 Subclasses cursor.MySQLCursor

10.6.1 cursor.MySQLCursorBuffered Class

10.6.2 cursor.MySQLCursorRaw Class

10.6.3 cursor.MySQLCursorBufferedRaw Class

10.6.4 cursor.MySQLCursorDict Class

10.6.5 cursor.MySQLCursorBufferedDict Class

10.6.6 cursor.MySQLCursorNamedTuple Class

10.6.7 cursor.MySQLCursorBufferedNamedTuple Class

10.6.8 cursor.MySQLCursorPrepared Class

10.7 constants.ClientFlag Class

10.8 constants.FieldType Class

10.9 constants.SQLMode Class

10.10 constants.CharacterSet Class

10.11 constants.RefreshOption Class

10.12 Errors and Exceptions

10.12.1 errorcode Module

10.12.2 errors.Error Exception

10.12.3 errors.DataError Exception

10.12.4 errors.DatabaseError Exception

10.12.5 errors.IntegrityError Exception

10.12.6 errors.InterfaceError Exception

10.12.7 errors.InternalError Exception

10.12.8 errors.NotSupportedError Exception

10.12.9 errors.OperationalError Exception

10.12.10 errors.PoolError Exception

10.12.11 errors.ProgrammingError Exception

10.12.12 errors.Warning Exception

10.12.13 errors.custom_error_exception() Function

This chapter contains the public API reference for Connector/Python. Examples should be considered working for Python 2.7, and Python 3.1 and greater. They might also work for older versions (such as Python 2.4) unless they use features introduced in newer Python versions. For example, exception handling using the as keyword was introduced in Python 2.6 and will not work in Python 2.4.

The following overview shows the mysql.connector package with its modules. Currently, only the most useful modules, classes, and methods for end users are documented.

mysql.connector
  errorcode
  errors
  connection
  constants
  conversion
  cursor
  dbapi
  locales
    eng
      client_error
  protocol
  utils

10.1 mysql.connector Module

The mysql.connector module provides top-level methods and properties.

10.1.1 mysql.connector.connect() Method

This method sets up a connection, establishing a session with the MySQL server. If no arguments are given, it uses the already configured or default values. For a complete list of possible arguments, see Section 7.1, “Connector/Python Connection Arguments”.

A connection with the MySQL server can be established using either the mysql.connector.connect() method or the mysql.connector.MySQLConnection() class:

cnx = mysql.connector.connect(user='joe', database='test')
cnx = MySQLConnection(user='joe', database='test')

For descriptions of connection methods and properties, see Section 10.2, “connection.MySQLConnection Class”.

10.1.2 mysql.connector.apilevel Property

This property is a string that indicates the supported DB API level.

>>> mysql.connector.apilevel
'2.0'

10.1.3 mysql.connector.paramstyle Property

This property is a string that indicates the Connector/Python default parameter style.

>>> mysql.connector.paramstyle
'pyformat'

10.1.4 mysql.connector.threadsafety Property

This property is an integer that indicates the supported level of thread safety provided by Connector/Python.

>>> mysql.connector.threadsafety
1

10.1.5 mysql.connector.__version__ Property

This property indicates the Connector/Python version as a string. It is available as of Connector/Python 1.1.0.

>>> mysql.connector.__version__
'1.1.0'

10.1.6 mysql.connector.__version_info__ Property

This property indicates the Connector/Python version as an array of version components. It is available as of Connector/Python 1.1.0.

>>> mysql.connector.__version_info__
(1, 1, 0, 'a', 0)

10.2 connection.MySQLConnection Class

The MySQLConnection class is used to open and manage a connection to a MySQL server. It also used to send commands and SQL statements and read the results.

10.2.1 connection.MySQLConnection() Constructor

Syntax:

cnx = MySQLConnection(**kwargs)

The MySQLConnection constructor initializes the attributes and when at least one argument is passed, it tries to connect to the MySQL server.

For a complete list of arguments, see Section 7.1, “Connector/Python Connection Arguments”.

10.2.2 MySQLConnection.close() Method

Syntax:

cnx.close()

close() is a synonym for disconnect(). See Section 10.2.20, “MySQLConnection.disconnect() Method”.

For a connection obtained from a connection pool, close() does not actually close it but returns it to the pool and makes it available for subsequent connection requests. See Section 9.1, “Connector/Python Connection Pooling”.

10.2.3 MySQLConnection.commit() Method

This method sends a COMMIT statement to the MySQL server, committing the current transaction. Since by default Connector/Python does not autocommit, it is important to call this method after every transaction that modifies data for tables that use transactional storage engines.

>>> cursor.execute("INSERT INTO employees (first_name) VALUES (%s)", ('Jane'))
>>> cnx.commit()

To roll back instead and discard modifications, see the rollback() method.

10.2.4 MySQLConnection.config() Method

Syntax:

cnx.config(**kwargs)

Configures a MySQLConnection instance after it has been instantiated. For a complete list of possible arguments, see Section 7.1, “Connector/Python Connection Arguments”.

Arguments:

kwargs: Connection arguments.

You could use the config() method to change (for example) the user name, then call reconnect().

Example:

cnx = mysql.connector.connect(user='joe', database='test')
# Connected as 'joe'
cnx.config(user='jane')
cnx.reconnect()
# Now connected as 'jane'

For a connection obtained from a connection pool, config() raises an exception. See Section 9.1, “Connector/Python Connection Pooling”.

10.2.5 MySQLConnection.connect() Method

Syntax:

MySQLConnection.connect(**kwargs)

This method sets up a connection, establishing a session with the MySQL server. If no arguments are given, it uses the already configured or default values. For a complete list of possible arguments, see Section 7.1, “Connector/Python Connection Arguments”.

Arguments:

kwargs: Connection arguments.

Example:

cnx = MySQLConnection(user='joe', database='test')

For a connection obtained from a conection pool, the connection object class is PooledMySQLConnection. A pooled connection differs from an unpooled connection as described in Section 9.1, “Connector/Python Connection Pooling”.

10.2.6 MySQLConnection.cursor() Method

Syntax:

cursor = cnx.cursor([arg=value[, arg=value]...])

This method returns a MySQLCursor() object, or a subclass of it depending on the passed arguments. The returned object is a cursor.CursorBase instance. For more information about cursor objects, see Section 10.5, “cursor.MySQLCursor Class”, and Section 10.6, “Subclasses cursor.MySQLCursor”.

Arguments may be passed to the cursor() method to control what type of cursor to create:

If buffered is True, the cursor fetches all rows from the server after an operation is executed. This is useful when queries return small result sets. buffered can be used alone, or in combination with the dictionary or named_tuple argument.

buffered can also be passed to connect() to set the default buffering mode for all cursors created from the connection object. See Section 7.1, “Connector/Python Connection Arguments”.

For information about the implications of buffering, see Section 10.6.1, “cursor.MySQLCursorBuffered Class”.

If raw is True, the cursor skips the conversion from MySQL data types to Python types when fetching rows. A raw cursor is usually used to get better performance or when you want to do the conversion yourself.

raw can also be passed to connect() to set the default raw mode for all cursors created from the connection object. See Section 7.1, “Connector/Python Connection Arguments”.

If dictionary is True, the cursor returns rows as dictionaries. This argument is available as of Connector/Python 2.0.0.

If named_tuple is True, the cursor returns rows as named tuples. This argument is available as of Connector/Python 2.0.0.

If prepared is True, the cursor is used for executing prepared statements. This argument is available as of Connector/Python 1.1.2.

The cursor_class argument can be used to pass a class to use for instantiating a new cursor. It must be a subclass of cursor.CursorBase.

The returned object depends on the combination of the arguments. Examples:

If not buffered and not raw: MySQLCursor

If buffered and not raw: MySQLCursorBuffered

If not buffered and raw: MySQLCursorRaw

If buffered and raw: MySQLCursorBufferedRaw

10.2.7 MySQLConnection.cmd_change_user() Method

Changes the user using username and password. It also causes the specified database to become the default (current) database. It is also possible to change the character set using the charset argument.

Syntax:

cnx.cmd_change_user(username='', password='', database='', charset=33)

Returns a dictionary containing the OK packet information.

10.2.8 MySQLConnection.cmd_debug() Method

Instructs the server to write debugging information to the error log. The connected user must have the SUPER privilege.

Returns a dictionary containing the OK packet information.

10.2.9 MySQLConnection.cmd_init_db() Method

Syntax:

cnx.cmd_init_db(db_name)

This method makes specified database the default (current) database. In subsequent queries, this database is the default for table references that include no explicit database qualifier.

Returns a dictionary containing the OK packet information.

10.2.10 MySQLConnection.cmd_ping() Method

Checks whether the connection to the server is working.

This method is not to be used directly. Use ping() or is_connected() instead.

Returns a dictionary containing the OK packet information.

10.2.11 MySQLConnection.cmd_process_info() Method

This method raises the NotSupportedError exception. Instead, use the SHOW PROCESSLIST statement or query the tables found in the database INFORMATION_SCHEMA.

10.2.12 MySQLConnection.cmd_process_kill() Method

Syntax:

cnx.cmd_process_kill(mysql_pid)

Asks the server to kill the thread specified by mysql_pid. Although still available, it is better to use the KILL SQL statement.

Returns a dictionary containing the OK packet information.

The following two lines have the same effect:

>>> cnx.cmd_process_kill(123)
>>> cnx.cmd_query('KILL 123')

10.2.13 MySQLConnection.cmd_query() Method

Syntax:

cnx.cmd_query(statement)

This method sends the given statement to the MySQL server and returns a result. To send multiple statements, use the cmd_query_iter() method instead.

The returned dictionary contains information depending on what kind of query was executed. If the query is a SELECT statement, the result contains information about columns. Other statements return a dictionary containing OK or EOF packet information.

Errors received from the MySQL server are raised as exceptions. An InterfaceError is raised when multiple results are found.

Returns a dictionary.

10.2.14 MySQLConnection.cmd_query_iter() Method

Syntax:

cnx.cmd_query_iter(statement)

Similar to the cmd_query() method, but returns a generator object to iterate through results. Use cmd_query_iter() when sending multiple statements, and separate the statements with semicolons.

The following example shows how to iterate through the results after sending multiple statements:

statement = 'SELECT 1; INSERT INTO t1 VALUES (); SELECT 2'
for result in cnx.cmd_query_iter(statement):
  if 'columns' in result:
    columns = result['columns']
    rows = cnx.get_rows()
  else:
    # do something useful with INSERT result

Returns a generator object.

10.2.15 MySQLConnection.cmd_quit() Method

This method sends a QUIT command to the MySQL server, closing the current connection. Since there is no response from the MySQL server, the packet that was sent is returned.

10.2.16 MySQLConnection.cmd_refresh() Method

Syntax:

cnx.cmd_refresh(options)

This method flushes tables or caches, or resets replication server information. The connected user must have the RELOAD privilege.

The options argument should be a bitmask value constructed using constants from the constants.RefreshOption class.

For a list of options, see Section 10.11, “constants.RefreshOption Class”.

Example:

>>> from mysql.connector import RefreshOption
>>> refresh = RefreshOption.LOG | RefreshOption.THREADS
>>> cnx.cmd_refresh(refresh)

10.2.17 MySQLConnection.cmd_reset_connection() Method

Syntax:

cnx.cmd_reset_connection()

Resets the connection by sending a COM_RESET_CONNECTION command to the server to clear the session state.

This method permits the session state to be cleared without reauthenticating. For MySQL servers older than 5.7.3 (when COM_RESET_CONNECTION was introduced), the reset_session() method can be used instead. That method resets the session state by reauthenticating, which is more expensive.

This method was added in Connector/Python 1.2.1.

10.2.18 MySQLConnection.cmd_shutdown() Method

Asks the database server to shut down. The connected user must have the SHUTDOWN privilege.

Returns a dictionary containing the OK packet information.

10.2.19 MySQLConnection.cmd_statistics() Method

Returns a dictionary containing information about the MySQL server including uptime in seconds and the number of running threads, questions, reloads, and open tables.

10.2.20 MySQLConnection.disconnect() Method

This method tries to send a QUIT command and close the socket. It raises no exceptions.

MySQLConnection.close() is a synonymous method name and more commonly used.

To shut down the connection without sending a QUIT command first, use shutdown().

10.2.21 MySQLConnection.get_row() Method

This method retrieves the next row of a query result set, returning a tuple.

The tuple returned by get_row() consists of:

The row as a tuple containing byte objects, or None when no more rows are available.

EOF packet information as a dictionary containing status_flag and warning_count, or None when the row returned is not the last row.

The get_row() method is used by MySQLCursor to fetch rows.

10.2.22 MySQLConnection.get_rows() Method

Syntax:

cnx.get_rows(count=None)

This method retrieves all or remaining rows of a query result set, returning a tuple containing the rows as sequences and the EOF packet information. The count argument can be used to obtain a given number of rows. If count is not specified or is None, all rows are retrieved.

The tuple returned by get_rows() consists of:

A list of tuples containing the row data as byte objects, or an empty list when no rows are available.

EOF packet information as a dictionary containing status_flag and warning_count.

An InterfaceError is raised when all rows have been retrieved.

MySQLCursor uses the get_rows() method to fetch rows.

Returns a tuple.

10.2.23 MySQLConnection.get_server_info() Method

This method returns the MySQL server information verbatim as a string, for example '5.6.11-log', or None when not connected.

10.2.24 MySQLConnection.get_server_version() Method

This method returns the MySQL server version as a tuple, or None when not connected.

10.2.25 MySQLConnection.is_connected() Method

Reports whether the connection to MySQL Server is available.

This method checks whether the connection to MySQL is available using the ping() method, but unlike ping(), is_connected() returns True when the connection is available, False otherwise.

10.2.26 MySQLConnection.isset_client_flag() Method

Syntax:

cnx.isset_client_flag(flag)

This method returns True if the client flag was set, False otherwise.

10.2.27 MySQLConnection.ping() Method

Syntax:

cnx.ping(attempts=1, delay=0)

Check whether the connection to the MySQL server is still available.

When reconnect is set to True, one or more attempts are made to try to reconnect to the MySQL server using the reconnect() method. Use the delay argument (seconds) if you want to wait between each retry.

When the connection is not available, an InterfaceError is raised. Use the is_connected() method to check the connection without raising an error.

Raises InterfaceError on errors.

10.2.28 MySQLConnection.reconnect() Method

Syntax:

cnx.reconnect(attempts=1, delay=0)

Attempt to reconnect to the MySQL server.

The argument attempts specifies the number of times a reconnect is tried. The delay argument is the number of seconds to wait between each retry.

You might set the number of attempts higher and use a longer delay when you expect the MySQL server to be down for maintenance, or when you expect the network to be temporarily unavailable.

10.2.29 MySQLConnection.reset_session() Method

Syntax:

cnx.reset_session(user_variables = None, session_variables = None)

Resets the connection by reauthenticating to clear the session state. user_variables, if given, is a dictionary of user variable names and values. session_variables, if given, is a dictionary of system variable names and values. The method sets each variable to the given value.

Example:

user_variables = {'var1': '1', 'var2': '10'}
session_variables = {'wait_timeout': 100000, 'sql_mode': 'TRADITIONAL'}
self.cnx.reset_session(user_variables, session_variables)

This method resets the session state by reauthenticating, which is expensive. For MySQL servers 5.7.3 or higher, the cmd_reset_connection() method can be used instead. It is more lightweight because it permits the session state to be cleared without reauthenticating.

This method was added in Connector/Python 1.2.1.

10.2.30 MySQLConnection.rollback() Method

This method sends a ROLLBACK statement to the MySQL server, undoing all data changes from the current transaction. By default, Connector/Python does not autocommit, so it is possible to cancel transactions when using transactional storage engines such as InnoDB.

>>> cursor.execute("INSERT INTO employees (first_name) VALUES (%s)", ('Jane'))
>>> cnx.rollback()

To commit modifications, see the commit() method.

10.2.31 MySQLConnection.set_charset_collation() Method

Syntax:

cnx.set_charset_collation(charset=None, collation=None)

This method sets the character set and collation to be used for the current connection. The charset argument can be either the name of a character set, or the numerical equivalent as defined in constants.CharacterSet.

When collation is None, the default collation for the character set is used.

In the following example, we set the character set to latin1 and the collation to latin1_swedish_ci (the default collation for: latin1):

>>> cnx = mysql.connector.connect(user='scott')
>>> cnx.set_charset_collation('latin1')

Specify a given collation as follows:

>>> cnx = mysql.connector.connect(user='scott')
>>> cnx.set_charset_collation('latin1', 'latin1_general_ci')

10.2.32 MySQLConnection.set_client_flags() Method

Syntax:

cnx.set_client_flags(flags)

This method sets the client flags to use when connecting to the MySQL server, and returns the new value as an integer. The flags argument can be either an integer or a sequence of valid client flag values (see Section 10.7, “constants.ClientFlag Class”).

If flags is a sequence, each item in the sequence sets the flag when the value is positive or unsets it when negative. For example, to unset LONG_FLAG and set the FOUND_ROWS flags:

>>> from mysql.connector.constants import ClientFlag
>>> cnx.set_client_flags([ClientFlag.FOUND_ROWS, -ClientFlag.LONG_FLAG])
>>> cnx.reconnect()

Note

Client flags are only set or used when connecting to the MySQL server. It is therefore necessary to reconnect after making changes.

10.2.33 MySQLConnection.shutdown() Method

This method closes the socket. It raises no exceptions.

Unlike disconnect(), shutdown() closes the client connection without attempting to send a QUIT command to the server first. Thus, it will not block if the connection is disrupted for some reason such as network failure.

shutdown() was added in Connector/Python 2.0.1.

10.2.34 MySQLConnection.start_transaction() Method

This method starts a transaction. It accepts arguments indicating whether to use a consistent snapshot, which transaction isolation level to use, and the transaction access mode:

cnx.start_transaction(consistent_snapshot=bool,
                      isolation_level=level,
                      readonly=access_mode)

The default consistent_snapshot value is False. If the value is True, Connector/Python sends WITH CONSISTENT SNAPSHOT with the statement. MySQL ignores this for isolation levels for which that option does not apply.

The default isolation_level value is None, and permitted values are 'READ UNCOMMITTED', 'READ COMMITTED', 'REPEATABLE READ', and 'SERIALIZABLE'. If the isolation_level value is None, no isolation level is sent, so the default level applies.

The readonly argument can be True to start the transaction in READ ONLY mode or False to start it in READ WRITE mode. If readonly is omitted, the server's default access mode is used. For details about transaction access mode, see the description for the START TRANSACTION statement at START TRANSACTION, COMMIT, and ROLLBACK Syntax. If the server is older than MySQL 5.6.5, it does not support setting the access mode and Connector/Python raises a ValueError.

Invoking start_transaction() raises a ProgrammingError if invoked while a transaction is currently in progress. This differs from executing a START TRANSACTION SQL statement while a transaction is in progress; the statement implicitly commits the current transaction.

To determine whether a transaction is active for the connection, use the in_transaction property.

start_transaction() was added in MySQL Connector/Python 1.1.0. The readonly argument was added in Connector/Python 1.1.5.

10.2.35 MySQLConnection.autocommit Property

This property can be assigned a value of True or False to enable or disable the autocommit feature of MySQL. The property can be invoked to retrieve the current autocommit setting.

Note

Autocommit is disabled by default when connecting through Connector/Python. This can be enabled using the autocommit connection parameter.

When the autocommit is turned off, you must commit transactions when using transactional storage engines such as InnoDB or NDBCluster.

>>> cnx.autocommit
False
>>> cnx.autocommit = True
>>> cnx.autocommit
True

10.2.36 MySQLConnection.can_consume_results Property

This property indicates the value of the consume_results connection parameter that controls whether result sets produced by queries are automatically read and discarded. See Section 7.1, “Connector/Python Connection Arguments”.

This method was added in Connector/Python 2.1.1.

10.2.37 MySQLConnection.charset Property

This property returns a string indicating which character set is used for the connection, whether or not it is connected.

10.2.38 MySQLConnection.collation Property

This property returns a string indicating which collation is used for the connection, whether or not it is connected.

10.2.39 MySQLConnection.connection_id Property

This property returns the integer connection ID (thread ID or session ID) for the current connection or None when not connected.

10.2.40 MySQLConnection.database Property

This property sets the current (default) database by executing a USE statement. The property can also be used to retrieve the current database name.

>>> cnx.database = 'test'
>>> cnx.database = 'mysql'
>>> cnx.database
u'mysql'

Returns a string.

10.2.41 MySQLConnection.get_warnings Property

This property can be assigned a value of True or False to enable or disable whether warnings should be fetched automatically. The default is False (default). The property can be invoked to retrieve the current warnings setting.

Fetching warnings automatically can be useful when debugging queries. Cursors make warnings available through the method MySQLCursor.fetchwarnings().

>>> cnx.get_warnings = True
>>> cursor.execute('SELECT "a"+1')
>>> cursor.fetchall()
[(1.0,)]
>>> cursor.fetchwarnings()
[(u'Warning', 1292, u"Truncated incorrect DOUBLE value: 'a'")]

Returns True or False.

10.2.42 MySQLConnection.in_transaction Property

This property returns True or False to indicate whether a transaction is active for the connection. The value is True regardless of whether you start a transaction using the start_transaction() API call or by directly executing an SQL statement such as START TRANSACTION or BEGIN.

>>> cnx.start_transaction()
>>> cnx.in_transaction
True
>>> cnx.commit()
>>> cnx.in_transaction
False

in_transaction was added in MySQL Connector/Python 1.1.0.

10.2.43 MySQLConnection.raise_on_warnings Property

This property can be assigned a value of True or False to enable or disable whether warnings should raise exceptions. The default is False (default). The property can be invoked to retrieve the current exceptions setting.

Setting raise_on_warnings also sets get_warnings because warnings need to be fetched so they can be raised as exceptions.

Note

You might always want to set the SQL mode if you would like to have the MySQL server directly report warnings as errors (see Section 10.2.46, “MySQLConnection.sql_mode Property”). It is also good to use transactional engines so transactions can be rolled back when catching the exception.

Result sets needs to be fetched completely before any exception can be raised. The following example shows the execution of a query that produces a warning:

>>> cnx.raise_on_warnings = True
>>> cursor.execute('SELECT "a"+1')
>>> cursor.fetchall()
..
mysql.connector.errors.DataError: 1292: Truncated incorrect DOUBLE value: 'a'

Returns True or False.

10.2.44 MySQLConnection.server_host Property

This read-only property returns the host name or IP address used for connecting to the MySQL server.

Returns a string.

10.2.45 MySQLConnection.server_port Property

This read-only property returns the TCP/IP port used for connecting to the MySQL server.

Returns an integer.

10.2.46 MySQLConnection.sql_mode Property

This property is used to retrieve and set the SQL Modes for the current connection. The value should be a list of different modes separated by comma (","), or a sequence of modes, preferably using the constants.SQLMode class.

To unset all modes, pass an empty string or an empty sequence.

>>> cnx.sql_mode = 'TRADITIONAL,NO_ENGINE_SUBSTITUTION'
>>> cnx.sql_mode.split(',')
[u'STRICT_TRANS_TABLES', u'STRICT_ALL_TABLES', u'NO_ZERO_IN_DATE',
u'NO_ZERO_DATE', u'ERROR_FOR_DIVISION_BY_ZERO', u'TRADITIONAL',
u'NO_AUTO_CREATE_USER', u'NO_ENGINE_SUBSTITUTION']

>>> from mysql.connector.constants import SQLMode
>>> cnx.sql_mode = [ SQLMode.NO_ZERO_DATE, SQLMode.REAL_AS_FLOAT]
>>> cnx.sql_mode

u'REAL_AS_FLOAT,NO_ZERO_DATE'

Returns a string.

10.2.47 MySQLConnection.time_zone Property

This property is used to set or retrieve the time zone session variable for the current connection.

>>> cnx.time_zone = '+00:00'
>>> cursor = cnx.cursor()
>>> cursor.execute('SELECT NOW()') ; cursor.fetchone()
(datetime.datetime(2012, 6, 15, 11, 24, 36),)
>>> cnx.time_zone = '-09:00'
>>> cursor.execute('SELECT NOW()') ; cursor.fetchone()
(datetime.datetime(2012, 6, 15, 2, 24, 44),)
>>> cnx.time_zone
u'-09:00'

Returns a string.

10.2.48 MySQLConnection.unix_socket Property

This read-only property returns the Unix socket file for connecting to the MySQL server.

Returns a string.

10.2.49 MySQLConnection.user Property

This read-only property returns the user name used for connecting to the MySQL server.

Returns a string.

10.3 pooling.MySQLConnectionPool Class

This class provides for the instantiation and management of connection pools.

10.3.1 pooling.MySQLConnectionPool Constructor

Syntax:

MySQLConnectionPool(pool_name=None,
                    pool_size=5,
                    pool_reset_session=True,
                    **kwargs)

This constructor instantiates an object that manages a connection pool.

Arguments:

pool_name: The pool name. If this argument is not given, Connector/Python automatically generates the name, composed from whichever of the host, port, user, and database connection arguments are given in kwargs, in that order.

It is not an error for multiple pools to have the same name. An application that must distinguish pools by their pool_name property should create each pool with a distinct name.

pool_size: The pool size. If this argument is not given, the default is 5.

pool_reset_session: Whether to reset session variables when the connection is returned to the pool. This argument was added in Connector/Python 1.1.5. Before 1.1.5, session variables are not reset.

kwargs: Optional additional connection arguments, as described in Section 7.1, “Connector/Python Connection Arguments”.

Example:

dbconfig = {
  "database": "test",
  "user":     "joe",
}

cnxpool = mysql.connector.pooling.MySQLConnectionPool(pool_name = "mypool",
                                                      pool_size = 3,
                                                      **dbconfig)

10.3.2 MySQLConnectionPool.add_connection() Method

Syntax:

cnxpool.add_connection(cnx = None)

This method adds a new or existing MySQLConnection to the pool, or raises a PoolError if the pool is full.

Arguments:

cnx: The MySQLConnection object to be added to the pool. If this argument is missing, the pool creates a new connection and adds it.

Example:

cnxpool.add_connection()    # add new connection to pool
cnxpool.add_connection(cnx) # add existing connection to pool

10.3.3 MySQLConnectionPool.get_connection() Method

Syntax:

cnxpool.get_connection()

This method returns a connection from the pool, or raises a PoolError if no connections are available.

Example:

cnx = cnxpool.get_connection()

10.3.4 MySQLConnectionPool.set_config() Method

Syntax:

cnxpool.set_config(**kwargs)

This method sets the configuration parameters for connections in the pool. Connections requested from the pool after the configuration change use the new parameters. Connections obtained before the change remain unaffected, but when they are closed (returned to the pool) are reopened with the new parameters before being returned by the pool for subsequent connection requests.

Arguments:

kwargs: Connection arguments.

Example:

dbconfig = {
  "database": "performance_schema",
  "user":     "admin",
  "password": "secret",
}

cnxpool.set_config(**dbconfig)

10.3.5 MySQLConnectionPool.pool_name Property

Syntax:

cnxpool.pool_name

This property returns the connection pool name.

Example:

name = cnxpool.pool_name

10.4 pooling.PooledMySQLConnection Class

This class is used by MySQLConnectionPool to return a pooled connection instance. It is also the class used for connections obtained with calls to the connect() method that name a connection pool (see Section 9.1, “Connector/Python Connection Pooling”).

PooledMySQLConnection pooled connection objects are similar to MySQLConnection unpooled connection objects, with these differences:

To release a pooled connection obtained from a connection pool, invoke its close() method, just as for any unpooled connection. However, for a pooled connection, close() does not actually close the connection but returns it to the pool and makes it available for subsequent connection requests.

A pooled connection cannot be reconfigured using its config() method. Connection changes must be done through the pool object itself, as described shortly.

A pooled connection has a pool_name property that returns the pool name.

10.4.1 pooling.PooledMySQLConnection Constructor

Syntax:

PooledMySQLConnection(cnxpool, cnx)

This constructor takes connection pool and connection arguments and returns a pooled connection. It is used by the MySQLConnectionPool class.

Arguments:

cnxpool: A MySQLConnectionPool instance.

cnx: A MySQLConnection instance.

Example:

pcnx = mysql.connector.pooling.PooledMySQLConnection(cnxpool, cnx)

10.4.2 PooledMySQLConnection.close() Method

Syntax:

cnx.close()

Returns a pooled connection to its connection pool.

For a pooled connection, close() does not actually close it but returns it to the pool and makes it available for subsequent connection requests.

If the pool configuration parameters are changed, a returned connection is closed and reopened with the new configuration before being returned from the pool again in response to a connection request.

10.4.3 PooledMySQLConnection.config() Method

For pooled connections, the config() method raises a PoolError exception. Configuration for pooled connections should be done using the pool object.

10.4.4 PooledMySQLConnection.pool_name Property

Syntax:

cnx.pool_name

This property returns the name of the connection pool to which the connection belongs.

Example:

cnx = cnxpool.get_connection()
name = cnx.pool_name

10.5 cursor.MySQLCursor Class

The MySQLCursor class instantiates objects that can execute operations such as SQL statements. Cursor objects interact with the MySQL server using a MySQLConnection object.

To create a cursor, use the cursor() method of a connection object:

import mysql.connector

cnx = mysql.connector.connect(database='world')
cursor = cnx.cursor()

Several related classes inherit from MySQLCursor. To create a cursor of one of these types, pass the appropriate arguments to cursor():

MySQLCursorBuffered creates a buffered cursor. See Section 10.6.1, “cursor.MySQLCursorBuffered Class”.

cursor = cnx.cursor(buffered=True)

MySQLCursorRaw creates a raw cursor. See Section 10.6.2, “cursor.MySQLCursorRaw Class”.

cursor = cnx.cursor(raw=True)

MySQLCursorBufferedRaw creates a buffered raw cursor. See Section 10.6.3, “cursor.MySQLCursorBufferedRaw Class”.

cursor = cnx.cursor(raw=True, buffered=True)

MySQLCursorDict creates a cursor that returns rows as dictionaries. See Section 10.6.4, “cursor.MySQLCursorDict Class”.

cursor = cnx.cursor(dictionary=True)

MySQLCursorBufferedDict creates a buffered cursor that returns rows as dictionaries. See Section 10.6.5, “cursor.MySQLCursorBufferedDict Class”.

cursor = cnx.cursor(dictionary=True, buffered=True)

MySQLCursorNamedTuple creates a cursor that returns rows as named tuples. See Section 10.6.6, “cursor.MySQLCursorNamedTuple Class”.

cursor = cnx.cursor(named_tuple=True)

MySQLCursorBufferedNamedTuple creates a buffered cursor that returns rows as named tuples. See Section 10.6.7, “cursor.MySQLCursorBufferedNamedTuple Class”.

cursor = cnx.cursor(named_tuple=True, buffered=True)

MySQLCursorPrepared creates a cursor for executing prepared statements. See Section 10.6.8, “cursor.MySQLCursorPrepared Class”.

cursor = cnx.cursor(prepared=True)

10.5.1 cursor.MySQLCursor Constructor

In most cases, the MySQLConnection cursor() method is used to instantiate a MySQLCursor object:

import mysql.connector

cnx = mysql.connector.connect(database='world')
cursor = cnx.cursor()

It is also possible to instantiate a cursor by passing a MySQLConnection object to MySQLCursor:

import mysql.connector
from mysql.connector.cursor import MySQLCursor

cnx = mysql.connector.connect(database='world')
cursor = MySQLCursor(cnx)

The connection argument is optional. If omitted, the cursor is created but its execute() method raises an exception.

10.5.2 MySQLCursor.callproc() Method

Syntax:

result_args = cursor.callproc(proc_name, args=())

This method calls the stored procedure named by the proc_name argument. The args sequence of parameters must contain one entry for each argument that the procedure expects. callproc() returns a modified copy of the input sequence. Input parameters are left untouched. Output and input/output parameters may be replaced with new values.

Result sets produced by the stored procedure are automatically fetched and stored as MySQLCursorBuffered instances. For more information about using these result sets, see stored_results().

Suppose that a stored procedure takes two parameters, multiplies the values, and returns the product:

CREATE PROCEDURE multiply(IN pFac1 INT, IN pFac2 INT, OUT pProd INT)
BEGIN
  SET pProd := pFac1 * pFac2;
END;

The following example shows how to execute the multiply() procedure:

>>> args = (5, 6, 0) # 0 is to hold value of the OUT parameter pProd
>>> cursor.callproc('multiply', args)
('5', '6', 30L)

Connector/Python 1.2.1 and up permits parameter types to be specified. To do this, specify a parameter as a two-item tuple consisting of the parameter value and type. Suppose that a procedure sp1() has this definition:

CREATE PROCEDURE sp1(IN pStr1 VARCHAR(20), IN pStr2 VARCHAR(20),
                     OUT pConCat VARCHAR(100))
BEGIN
  SET pConCat := CONCAT(pStr1, pStr2);
END;

To execute this procedure from Connector/Python, specifying a type for the OUT parameter, do this:

args = ('ham', 'eggs', (0, 'CHAR'))
result_args = cursor.callproc('sp1', args)
print(result_args[2])

10.5.3 MySQLCursor.close() Method

Syntax:

cursor.close()

Use close() when you are done using a cursor. This method closes the cursor, resets all results, and ensures that the cursor object has no reference to its original connection object.

10.5.4 MySQLCursor.execute() Method

Syntax:

cursor.execute(operation, params=None, multi=False)
iterator = cursor.execute(operation, params=None, multi=True)

This method executes the given database operation (query or command). The parameters found in the tuple or dictionary params are bound to the variables in the operation. Specify variables using %s or %(name)s parameter style (that is, using format or pyformat style). execute() returns an iterator if multi is True.

This example inserts information about a new employee, then selects the data for that person. The statements are executed as separate execute() operations:

insert_stmt = (
  "INSERT INTO employees (emp_no, first_name, last_name, hire_date) "
  "VALUES (%s, %s, %s, %s)"
)
data = (2, 'Jane', 'Doe', datetime.date(2012, 3, 23))
cursor.execute(insert_stmt, data)

select_stmt = "SELECT * FROM employees WHERE emp_no = %(emp_no)s"
cursor.execute(select_stmt, { 'emp_no': 2 })

The data values are converted as necessary from Python objects to something MySQL understands. In the preceding example, the datetime.date() instance is converted to '2012-03-23'.

If multi is set to True, execute() is able to execute multiple statements specified in the operation string. It returns an iterator that enables processing the result of each statement. However, using parameters does not work well in this case, and it is usually a good idea to execute each statement on its own.

The following example selects and inserts data in a single execute() operation and displays the result of each statement:

operation = 'SELECT 1; INSERT INTO t1 VALUES (); SELECT 2'
for result in cursor.execute(operation, multi=True):
  if result.with_rows:
    print("Rows produced by statement '{}':".format(
      result.statement))
    print(result.fetchall())
  else:
    print("Number of rows affected by statement '{}': {}".format(
      result.statement, result.rowcount))

If the connection is configured to fetch warnings, warnings generated by the operation are available through the MySQLCursor.fetchwarnings() method.

10.5.5 MySQLCursor.executemany() Method

Syntax:

cursor.executemany(operation, seq_of_params)

This method prepares a database operation (query or command) and executes it against all parameter sequences or mappings found in the sequence seq_of_params.

In most cases, the executemany() method iterates through the sequence of parameters, each time passing the current parameters to the the execute() method.

An optimization is applied for inserts: The data values given by the parameter sequences are batched using multiple-row syntax. The following example inserts three records:

data = [
  ('Jane', date(2005, 2, 12)),
  ('Joe', date(2006, 5, 23)),
  ('John', date(2010, 10, 3)),
]
stmt = "INSERT INTO employees (first_name, hire_date) VALUES (%s, %s)"
cursor.executemany(stmt, data)

For the preceding example, the INSERT statement sent to MySQL is:

INSERT INTO employees (first_name, hire_date)
VALUES ('Jane', '2005-02-12'), ('Joe', '2006-05-23'), ('John', '2010-10-03')

With the executemany() method, it is not possible to specify multiple statements to execute in the operation argument. Doing so raises an InternalError exception. Consider using execute() with multi=True instead.

10.5.6 MySQLCursor.fetchall() Method

Syntax:

rows = cursor.fetchall()

The method fetches all (or all remaining) rows of a query result set and returns a list of tuples. If no more rows are available, it returns an empty list.

The following example shows how to retrieve the first two rows of a result set, and then retrieve any remaining rows:

>>> cursor.execute("SELECT * FROM employees ORDER BY emp_no")
>>> head_rows = cursor.fetchmany(size=2)
>>> remaining_rows = cursor.fetchall()

You must fetch all rows for the current query before executing new statements using the same connection.

10.5.7 MySQLCursor.fetchmany() Method

Syntax:

rows = cursor.fetchmany(size=1)

This method fetches the next set of rows of a query result and returns a list of tuples. If no more rows are available, it returns an empty list.

The number of rows returned can be specified using the size argument, which defaults to one. Fewer rows are returned if fewer rows are available than specified.

You must fetch all rows for the current query before executing new statements using the same connection.

10.5.8 MySQLCursor.fetchone() Method

Syntax:

row = cursor.fetchone()

This method retrieves the next row of a query result set and returns a single sequence, or None if no more rows are available. By default, the returned tuple consists of data returned by the MySQL server, converted to Python objects. If the cursor is a raw cursor, no such conversion occurs; see Section 10.6.2, “cursor.MySQLCursorRaw Class”.

The fetchone() method is used by fetchall() and fetchmany(). It is also used when a cursor is used as an iterator.

The following example shows two equivalent ways to process a query result. The first uses fetchone() in a while loop, the second uses the cursor as an iterator:

# Using a while loop
cursor.execute("SELECT * FROM employees")
row = cursor.fetchone()
while row is not None:
  print(row)
  row = cursor.fetchone()

# Using the cursor as iterator
cursor.execute("SELECT * FROM employees")
for row in cursor:
  print(row)

You must fetch all rows for the current query before executing new statements using the same connection.

10.5.9 MySQLCursor.fetchwarnings() Method

Syntax:

tuples = cursor.fetchwarnings()

This method returns a list of tuples containing warnings generated by the previously executed operation. To set whether to fetch warnings, use the connection's get_warnings property.

The following example shows a SELECT statement that generates a warning:

>>> cnx.get_warnings = True
>>> cursor.execute("SELECT 'a'+1")
>>> cursor.fetchall()
[(1.0,)]
>>> cursor.fetchwarnings()
[(u'Warning', 1292, u"Truncated incorrect DOUBLE value: 'a'")]

When warnings are generated, it is possible to raise errors instead, using the connection's raise_on_warnings property.

10.5.10 MySQLCursor.stored_results() Method

Syntax:

iterator = cursor.stored_results()

This method returns a list iterator object that can be used to process result sets produced by a stored procedure executed using the callproc() method. The result sets remain available until you use the cursor to execute another operation or call another stored procedure.

The following example executes a stored procedure that produces two result sets, then uses stored_results() to retrieve them:

>>> cursor.callproc('myproc')
()
>>> for result in cursor.stored_results():
...     print result.fetchall()
...
[(1,)]
[(2,)]

10.5.11 MySQLCursor.column_names Property

Syntax:

sequence = cursor.column_names

This read-only property returns the column names of a result set as sequence of Unicode strings.

The following example shows how to create a dictionary from a tuple containing data with keys using column_names:

cursor.execute("SELECT last_name, first_name, hire_date "
               "FROM employees WHERE emp_no = %s", (123,))
row = dict(zip(cursor.column_names, cursor.fetchone()))
print("{last_name}, {first_name}: {hire_date}".format(row))

Alternatively, as of Connector/Python 2.0.0, you can fetch rows as dictionaries directly; see Section 10.6.4, “cursor.MySQLCursorDict Class”.

10.5.12 MySQLCursor.description Property

Syntax:

tuples = cursor.description

This read-only property returns a list of tuples describing the columns in a result set. Each tuple in the list contains values as follows:

(column_name,
 type,
 None,
 None,
 None,
 None,
 null_ok,
 column_flags)

The following example shows how to interpret description tuples:

import mysql.connector
from mysql.connector import FieldType

...

cursor.execute("SELECT emp_no, last_name, hire_date "
               "FROM employees WHERE emp_no = %s", (123,))
for i in range(len(cursor.description)):
  print("Column {}:".format(i+1))
  desc = cursor.description[i]
  print("  column_name = {}".format(desc[0]))
  print("  type = {} ({})".format(desc[1], FieldType.get_info(desc[1])))
  print("  null_ok = {}".format(desc[6]))
  print("  column_flags = {}".format(desc[7]))

The output looks like this:

Column 1:
  column_name = emp_no
  type = 3 (LONG)
  null_ok = 0
  column_flags = 20483
Column 2:
  column_name = last_name
  type = 253 (VAR_STRING)
  null_ok = 0
  column_flags = 4097
Column 3:
  column_name = hire_date
  type = 10 (DATE)
  null_ok = 0
  column_flags = 4225

The column_flags value is an instance of the constants.FieldFlag class. To see how to interpret it, do this:

>>> from mysql.connector import FieldFlag
>>> FieldFlag.desc

10.5.13 MySQLCursor.lastrowid Property

Syntax:

id = cursor.lastrowid

This read-only property returns the value generated for an AUTO_INCREMENT column by the previous INSERT or UPDATE statement or None when there is no such value available. For example, if you perform an INSERT into a table that contains an AUTO_INCREMENT column, lastrowid returns the AUTO_INCREMENT value for the new row. For an example, see Section 5.3, “Inserting Data Using Connector/Python”.

The lastrowid property is like the mysql_insert_id() C API function; see mysql_insert_id().

10.5.14 MySQLCursor.rowcount Property

Syntax:

count = cursor.rowcount

This read-only property returns the number of rows returned for SELECT statements, or the number of rows affected by DML statements such as INSERT or UPDATE. For an example, see Section 10.5.4, “MySQLCursor.execute() Method”.

For nonbuffered cursors, the row count cannot be known before the rows have been fetched. In this case, the number of rows is -1 immediately after query execution and is incremented as rows are fetched.

The rowcount property is like the mysql_affected_rows() C API function; see mysql_affected_rows().

10.5.15 MySQLCursor.statement Property

Syntax:

str = cursor.statement

This read-only property returns the last executed statement as a string. The statement property can be useful for debugging and displaying what was sent to the MySQL server.

The string can contain multiple statements if a multiple-statement string was executed. This occurs for execute() with multi=True. In this case, the statement property contains the entire statement string and the execute() call returns an iterator that can be used to process results from the individual statements. The statement property for this iterator shows statement strings for the individual statements.

10.5.16 MySQLCursor.with_rows Property

Syntax:

boolean = cursor.with_rows

This read-only property returns True or False to indicate whether the most recently executed operation produced rows.

The with_rows property is useful when it is necessary to determine whether a statement produces a result set and you need to fetch rows. The following example retrieves the rows returned by the SELECT statements, but reports only the affected-rows value for the UPDATE statement:

import mysql.connector

cnx = mysql.connector.connect(user='scott', database='test')
cursor = cnx.cursor()
operation = 'SELECT 1; UPDATE t1 SET c1 = 2; SELECT 2'
for result in cursor.execute(operation, multi=True):
  if result.with_rows:
    result.fetchall()
  else:
    print("Number of affected rows: {}".format(result.rowcount))

10.6 Subclasses cursor.MySQLCursor

The cursor classes described in the following sections inherit from the MySQLCursor class, which is described in Section 10.5, “cursor.MySQLCursor Class”.

10.6.1 cursor.MySQLCursorBuffered Class

The MySQLCursorBuffered class inherits from MySQLCursor.

After executing a query, a MySQLCursorBuffered cursor fetches the entire result set from the server and buffers the rows.

For queries executed using a buffered cursor, row-fetching methods such as fetchone() return rows from the set of buffered rows. For nonbuffered cursors, rows are not fetched from the server until a row-fetching method is called. In this case, you must be sure to fetch all rows of the result set before executing any other statements on the same connection, or an InternalError (Unread result found) exception will be raised.

MySQLCursorBuffered can be useful in situations where multiple queries, with small result sets, need to be combined or computed with each other.

To create a buffered cursor, use the buffered argument when calling a connection's cursor() method. Alternatively, to make all cursors created from the connection buffered by default, use the buffered connection argument.

Example:

import mysql.connector

cnx = mysql.connector.connect()

# Only this particular cursor will buffer results
cursor = cnx.cursor(buffered=True)

# All cursors created from cnx2 will be buffered by default
cnx2 = mysql.connector.connect(buffered=True)

For a practical use case, see Section 6.1, “Tutorial: Raise Employee's Salary Using a Buffered Cursor”.

10.6.2 cursor.MySQLCursorRaw Class

The MySQLCursorRaw class inherits from MySQLCursor.

A MySQLCursorRaw cursor skips the conversion from MySQL data types to Python types when fetching rows. A raw cursor is usually used to get better performance or when you want to do the conversion yourself.

To create a raw cursor, use the raw argument when calling a connection's cursor() method. Alternatively, to make all cursors created from the connection raw by default, use the raw connection argument.

Example:

import mysql.connector

cnx = mysql.connector.connect()

# Only this particular cursor will be raw
cursor = cnx.cursor(raw=True)

# All cursors created from cnx2 will be raw by default
cnx2 = mysql.connector.connect(raw=True)

10.6.3 cursor.MySQLCursorBufferedRaw Class

The MySQLCursorBufferedRaw class inherits from MySQLCursor.

A MySQLCursorBufferedRaw cursor is like a MySQLCursorRaw cursor, but is buffered: After executing a query, it fetches the entire result set from the server and buffers the rows. For information about the implications of buffering, see Section 10.6.1, “cursor.MySQLCursorBuffered Class”.

To create a buffered raw cursor, use the raw and buffered arguments when calling a connection's cursor() method. Alternatively, to make all cursors created from the connection raw and buffered by default, use the raw and buffered connection arguments.

Example:

import mysql.connector

cnx = mysql.connector.connect()

# Only this particular cursor will be raw and buffered
cursor = cnx.cursor(raw=True, buffered=True)

# All cursors created from cnx2 will be raw and buffered by default
cnx2 = mysql.connector.connect(raw=True, buffered=True)

10.6.4 cursor.MySQLCursorDict Class

The MySQLCursorDict class inherits from MySQLCursor. This class is available as of Connector/Python 2.0.0.

A MySQLCursorDict cursor returns each row as a dictionary. The keys for each dictionary object are the column names of the MySQL result.

Example:

cnx = mysql.connector.connect(database='world')
cursor = cnx.cursor(dictionary=True)
cursor.execute("SELECT * FROM country WHERE Continent = 'Europe'")

print("Countries in Europe:")
for row in cursor:
    print("* {Name}".format(Name=row['Name']

The preceding code produces output like this:

Countries in Europe:
* Albania
* Andorra
* Austria
* Belgium
* Bulgaria
...

It may be convenient to pass the dictionary to format() as follows:

cursor.execute("SELECT Name, Population FROM country WHERE Continent = 'Europe'")

print("Countries in Europe with population:")
for row in cursor:
    print("* {Name}: {Population}".format(**row))

10.6.5 cursor.MySQLCursorBufferedDict Class

The MySQLCursorBufferedDict class inherits from MySQLCursor. This class is available as of Connector/Python 2.0.0.

A MySQLCursorBufferedDict cursor is like a MySQLCursorDict cursor, but is buffered: After executing a query, it fetches the entire result set from the server and buffers the rows. For information about the implications of buffering, see Section 10.6.1, “cursor.MySQLCursorBuffered Class”.

To get a buffered cursor that returns dictionaries, add the buffered argument when instantiating a new dictionary cursor:

cursor = cnx.cursor(dictionary=True, buffered=True)

10.6.6 cursor.MySQLCursorNamedTuple Class

The MySQLCursorNamedTuple class inherits from MySQLCursor. This class is available as of Connector/Python 2.0.0.

A MySQLCursorNamedTuple cursor returns each row as a named tuple. The attributes for each named-tuple object are the column names of the MySQL result.

Example:

cnx = mysql.connector.connect(database='world')
cursor = cnx.cursor(named_tuple=True)
cursor.execute("SELECT * FROM country WHERE Continent = 'Europe'")

print("Countries in Europe with population:")
for row in cursor:
    print("* {Name}: {Population}".format(
        Name=row.Name,
        Population=row.Population
    ))

10.6.7 cursor.MySQLCursorBufferedNamedTuple Class

The MySQLCursorBufferedNamedTuple class inherits from MySQLCursor. This class is available as of Connector/Python 2.0.0.

A MySQLCursorBufferedNamedTuple cursor is like a MySQLCursorNamedTuple cursor, but is buffered: After executing a query, it fetches the entire result set from the server and buffers the rows. For information about the implications of buffering, see Section 10.6.1, “cursor.MySQLCursorBuffered Class”.

To get a buffered cursor that returns named tuples, add the buffered argument when instantiating a new named-tuple cursor:

cursor = cnx.cursor(named_tuple=True, buffered=True)

10.6.8 cursor.MySQLCursorPrepared Class

The MySQLCursorPrepared class inherits from MySQLCursor. This class is available as of Connector/Python 1.1.0.

In MySQL, there are two ways to execute a prepared statement:

Use the PREPARE and EXECUTE statements.

Use the binary client/server protocol to send and receive data. To repeatedly execute the same statement with different data for different executions, this is more efficient than using PREPARE and EXECUTE. For information about the binary protocol, see C API Prepared Statements.

In Connector/Python, there are two ways to create a cursor that enables execution of prepared statements using the binary protocol. In both cases, the cursor() method of the connection object returns a MySQLCursorPrepared object:

The simpler syntax uses a prepared=True argument to the cursor() method. This syntax is available as of Connector/Python 1.1.2.

import mysql.connector

cnx = mysql.connector.connect(database='employees')
cursor = cnx.cursor(prepared=True)

Alternatively, create an instance of the MySQLCursorPrepared class using the cursor_class argument to the cursor() method. This syntax is available as of Connector/Python 1.1.0.

import mysql.connector
from mysql.connector.cursor import MySQLCursorPrepared

cnx = mysql.connector.connect(database='employees')
cursor = cnx.cursor(cursor_class=MySQLCursorPrepared)

A cursor instantiated from the MySQLCursorPrepared class works like this:

The first time you pass a statement to the cursor's execute() method, it prepares the statement. For subsequent invocations of execute(), the preparation phase is skipped if the statement is the same.

The execute() method takes an optional second argument containing a list of data values to associate with parameter markers in the statement. If the list argument is present, there must be one value per parameter marker.

Example:

cursor = cnx.cursor(prepared=True)
stmt = "SELECT fullname FROM employees WHERE id = %s" # (1)
cursor.execute(stmt, (5,))                            # (2)
# ... fetch data ...
cursor.execute(stmt, (10,))                           # (3)
# ... fetch data ...

The %s within the statement is a parameter marker. Do not put quote marks around parameter markers.

For the first call to the execute() method, the cursor prepares the statement. If data is given in the same call, it also executes the statement and you should fetch the data.

For subsequent execute() calls that pass the same SQL statement, the cursor skips the preparation phase.

Prepared statements executed with MySQLCursorPrepared can use the format (%s) or qmark (?) parameterization style. This differs from nonprepared statements executed with MySQLCursor, which can use the format or pyformat parameterization style.

To use multiple prepared statements simultaneously, instantiate multiple cursors from the MySQLCursorPrepared class.

The MySQL client/server protocol has an option to send prepared statement parameters via the COM_STMT_SEND_LONG_DATA command. To use this from Connector/Python scripts, send the parameter in question using the IOBase interface. Example:

from io import IOBase

...

cur = cnx.cursor(prepared=True)
cur.execute("SELECT (%s)", (io.BytesIO(bytes("A", "latin1")), ))

10.7 constants.ClientFlag Class

This class provides constants defining MySQL client flags that can be used when the connection is established to configure the session. The ClientFlag class is available when importing mysql.connector.

>>> import mysql.connector
>>> mysql.connector.ClientFlag.FOUND_ROWS
2

See Section 10.2.32, “MySQLConnection.set_client_flags() Method” and the connection argument client_flag.

The ClientFlag class cannot be instantiated.

10.8 constants.FieldType Class

This class provides all supported MySQL field or data types. They can be useful when dealing with raw data or defining your own converters. The field type is stored with every cursor in the description for each column.

The following example shows how to print the name of the data type for each column in a result set.

from __future__ import print_function
import mysql.connector
from mysql.connector import FieldType

cnx = mysql.connector.connect(user='scott', database='test')
cursor = cnx.cursor()

cursor.execute(
  "SELECT DATE(NOW()) AS `c1`, TIME(NOW()) AS `c2`, "
  "NOW() AS `c3`, 'a string' AS `c4`, 42 AS `c5`")
rows = cursor.fetchall()

for desc in cursor.description:
  colname = desc[0]
  coltype = desc[1]
  print("Column {} has type {}".format(
    colname, FieldType.get_info(coltype)))

cursor.close()
cnx.close()

The FieldType class cannot be instantiated.

10.9 constants.SQLMode Class

This class provides all known MySQL Server SQL Modes. It is mostly used when setting the SQL modes at connection time using the connection's sql_mode property. See Section 10.2.46, “MySQLConnection.sql_mode Property”.

The SQLMode class cannot be instantiated.

10.10 constants.CharacterSet Class

This class provides all known MySQL characters sets and their default collations. For examples, see Section 10.2.31, “MySQLConnection.set_charset_collation() Method”.

The CharacterSet class cannot be instantiated.

10.11 constants.RefreshOption Class

This class performs various flush operations.

RefreshOption.GRANT

Refresh the grant tables, like FLUSH PRIVILEGES.

RefreshOption.LOG

Flush the logs, like FLUSH LOGS.

RefreshOption.TABLES

Flush the table cache, like FLUSH TABLES.

RefreshOption.HOSTS

Flush the host cache, like FLUSH HOSTS.

RefreshOption.STATUS

Reset status variables, like FLUSH STATUS.

RefreshOption.THREADS

Flush the thread cache.

RefreshOption.SLAVE

On a slave replication server, reset the master server information and restart the slave, like RESET SLAVE.

RefreshOption.MASTER

On a master replication server, remove the binary log files listed in the binary log index and truncate the index file, like RESET MASTER.

10.12 Errors and Exceptions

The mysql.connector.errors module defines exception classes for errors and warnings raised by MySQL Connector/Python. Most classes defined in this module are available when you import mysql.connector.

The exception classes defined in this module mostly follow the Python Database API Specification v2.0 (PEP 249). For some MySQL client or server errors it is not always clear which exception to raise. It is good to discuss whether an error should be reclassified by opening a bug report.

MySQL Server errors are mapped with Python exception based on their SQLSTATE value (see Server Error Codes and Messages). The following table shows the SQLSTATE classes and the exception Connector/Python raises. It is, however, possible to redefine which exception is raised for each server error. The default exception is DatabaseError.

Table 10.1 Mapping of Server Errors to Python Exceptions

SQLSTATE Class | Connector/Python Exception
02 | DataError
02 | DataError
07 | DatabaseError
08 | OperationalError
0A | NotSupportedError
21 | DataError
22 | DataError
23 | IntegrityError
24 | ProgrammingError
25 | ProgrammingError
26 | ProgrammingError
27 | ProgrammingError
28 | ProgrammingError
2A | ProgrammingError
2B | DatabaseError
2C | ProgrammingError
2D | DatabaseError
2E | DatabaseError
33 | DatabaseError
34 | ProgrammingError
35 | ProgrammingError
37 | ProgrammingError
3C | ProgrammingError
3D | ProgrammingError
3F | ProgrammingError
40 | InternalError
42 | ProgrammingError
44 | InternalError
HZ | OperationalError
XA | IntegrityError
0K | OperationalError
HY | DatabaseError

10.12.1 errorcode Module

This module contains both MySQL server and client error codes defined as module attributes with the error number as value. Using error codes instead of error numbers could make reading the source code a bit easier.

>>> from mysql.connector import errorcode
>>> errorcode.ER_BAD_TABLE_ERROR
1051

See Server Error Codes and Messages and Client Error Codes and Messages.

10.12.2 errors.Error Exception

This exception is the base class for all other exceptions in the errors module. It can be used to catch all errors in a single except statement.

The following example shows how we could catch syntax errors:

import mysql.connector

try:
  cnx = mysql.connector.connect(user='scott', database='employees')
  cursor = cnx.cursor()
  cursor.execute("SELECT * FORM employees")   # Syntax error in query
  cnx.close()
except mysql.connector.Error as err:
  print("Something went wrong: {}".format(err))

Initializing the exception supports a few optional arguments, namely msg, errno, values and sqlstate. All of them are optional and default to None. errors.Error is internally used by Connector/Python to raise MySQL client and server errors and should not be used by your application to raise exceptions.

The following examples show the result when using no arguments or a combination of the arguments:

>>> from mysql.connector.errors import Error
>>> str(Error())
'Unknown error'

>>> str(Error("Oops! There was an error."))
'Oops! There was an error.'

>>> str(Error(errno=2006))
'2006: MySQL server has gone away'

>>> str(Error(errno=2002, values=('/tmp/mysql.sock', 2)))
"2002: Can't connect to local MySQL server through socket '/tmp/mysql.sock' (2)"

>>> str(Error(errno=1146, sqlstate='42S02', msg="Table 'test.spam' doesn't exist"))
"1146 (42S02): Table 'test.spam' doesn't exist"

The example which uses error number 1146 is used when Connector/Python receives an error packet from the MySQL Server. The information is parsed and passed to the Error exception as shown.

Each exception subclassing from Error can be initialized using the previously mentioned arguments. Additionally, each instance has the attributes errno, msg and sqlstate which can be used in your code.

The following example shows how to handle errors when dropping a table which does not exist (when the DROP TABLE statement does not include a IF EXISTS clause):

import mysql.connector
from mysql.connector import errorcode

cnx = mysql.connector.connect(user='scott', database='test')
cursor = cnx.cursor()
try:
  cursor.execute("DROP TABLE spam")
except mysql.connector.Error as err:
  if err.errno == errorcode.ER_BAD_TABLE_ERROR:
    print("Creating table spam")
  else:
    raise

Prior to Connector/Python 1.1.1, the original message passed to errors.Error() is not saved in such a way that it could be retrieved. Instead, the Error.msg attribute was formatted with the error number and SQLSTATE value. As of 1.1.1, only the original message is saved in the Error.msg attribute. The formatted value together with the error number and SQLSTATE value can be obtained by printing or getting the string representation of the error object. Example:

try:
  conn = mysql.connector.connect(database = "baddb")
except mysql.connector.Error as e:
  print "Error code:", e.errno        # error number
  print "SQLSTATE value:", e.sqlstate # SQLSTATE value
  print "Error message:", e.msg       # error message
  print "Error:", e                   # errno, sqlstate, msg values
  s = str(e)
  print "Error:", s                   # errno, sqlstate, msg values

errors.Error is a subclass of the Python StandardError.

10.12.3 errors.DataError Exception

This exception is raised when there were problems with the data. Examples are a column set to NULL that cannot be NULL, out-of-range values for a column, division by zero, column count does not match value count, and so on.

errors.DataError is a subclass of errors.DatabaseError.

10.12.4 errors.DatabaseError Exception

This exception is the default for any MySQL error which does not fit the other exceptions.

errors.DatabaseError is a subclass of errors.Error.

10.12.5 errors.IntegrityError Exception

This exception is raised when the relational integrity of the data is affected. For example, a duplicate key was inserted or a foreign key constraint would fail.

The following example shows a duplicate key error raised as IntegrityError:

cursor.execute("CREATE TABLE t1 (id int, PRIMARY KEY (id))")
try:
  cursor.execute("INSERT INTO t1 (id) VALUES (1)")
  cursor.execute("INSERT INTO t1 (id) VALUES (1)")
except mysql.connector.IntegrityError as err:
  print("Error: {}".format(err))

errors.IntegrityError is a subclass of errors.DatabaseError.

10.12.6 errors.InterfaceError Exception

This exception is raised for errors originating from Connector/Python itself, not related to the MySQL server.

errors.InterfaceError is a subclass of errors.Error.

10.12.7 errors.InternalError Exception

This exception is raised when the MySQL server encounters an internal error, for example, when a deadlock occurred.

errors.InternalError is a subclass of errors.DatabaseError.

10.12.8 errors.NotSupportedError Exception

This exception is raised when some feature was used that is not supported by the version of MySQL that returned the error. It is also raised when using functions or statements that are not supported by stored routines.

errors.NotSupportedError is a subclass of errors.DatabaseError.

10.12.9 errors.OperationalError Exception

This exception is raised for errors which are related to MySQL's operations. For example: too many connections; a host name could not be resolved; bad handshake; server is shutting down, communication errors.

errors.OperationalError is a subclass of errors.DatabaseError.

10.12.10 errors.PoolError Exception

This exception is raised for connection pool errors. errors.PoolError is a subclass of errors.Error.

10.12.11 errors.ProgrammingError Exception

This exception is raised on programming errors, for example when you have a syntax error in your SQL or a table was not found.

The following example shows how to handle syntax errors:

try:
  cursor.execute("CREATE DESK t1 (id int, PRIMARY KEY (id))")
except mysql.connector.ProgrammingError as err:
  if err.errno == errorcode.ER_SYNTAX_ERROR:
    print("Check your syntax!")
  else:
    print("Error: {}".format(err))

errors.ProgrammingError is a subclass of errors.DatabaseError.

10.12.12 errors.Warning Exception

This exception is used for reporting important warnings, however, Connector/Python does not use it. It is included to be compliant with the Python Database Specification v2.0 (PEP-249).

Consider using either more strict Server SQL Modes or the raise_on_warnings connection argument to make Connector/Python raise errors when your queries produce warnings.

errors.Warning is a subclass of the Python StandardError.

10.12.13 errors.custom_error_exception() Function

Syntax:

errors.custom_error_exception(error=None, exception=None)

This method defines custom exceptions for MySQL server errors and returns current customizations.

If error is a MySQL Server error number, you must also pass the exception class. The error argument can be a dictionary, in which case the key is the server error number, and value the class of the exception to be raised.

To reset the customizations, supply an empty dictionary.

import mysql.connector
from mysql.connector import errorcode

# Server error 1028 should raise a DatabaseError
mysql.connector.custom_error_exception(1028, mysql.connector.DatabaseError)

# Or using a dictionary:
mysql.connector.custom_error_exception({
  1028: mysql.connector.DatabaseError,
  1029: mysql.connector.OperationalError,
})

# To reset, pass an empty dictionary:
mysql.connector.custom_error_exception({})

Chapter 11 Connector/Python C Extension API Reference

Table of Contents

11.1 _mysql_connector Module

11.2 _mysql_connector.MySQL() Class

11.3 _mysql_connector.MySQL.affected_rows() Method

11.4 _mysql_connector.MySQL.autocommit() Method

11.5 _mysql_connector.MySQL.buffered() Method

11.6 _mysql_connector.MySQL.change_user() Method

11.7 _mysql_connector.MySQL.character_set_name() Method

11.8 _mysql_connector.MySQL.close() Method

11.9 _mysql_connector.MySQL.commit() Method

11.10 _mysql_connector.MySQL.connect() Method

11.11 _mysql_connector.MySQL.connected() Method

11.12 _mysql_connector.MySQL.consume_result() Method

11.13 _mysql_connector.MySQL.convert_to_mysql() Method

11.14 _mysql_connector.MySQL.escape_string() Method

11.15 _mysql_connector.MySQL.fetch_fields() Method

11.16 _mysql_connector.MySQL.fetch_row() Method

11.17 _mysql_connector.MySQL.field_count() Method

11.18 _mysql_connector.MySQL.free_result() Method

11.19 _mysql_connector.MySQL.get_character_set_info() Method

11.20 _mysql_connector.MySQL.get_client_info() Method

11.21 _mysql_connector.MySQL.get_client_version() Method

11.22 _mysql_connector.MySQL.get_host_info() Method

11.23 _mysql_connector.MySQL.get_proto_info() Method

11.24 _mysql_connector.MySQL.get_server_info() Method

11.25 _mysql_connector.MySQL.get_server_version() Method

11.26 _mysql_connector.MySQL.get_ssl_cipher() Method

11.27 _mysql_connector.MySQL.hex_string() Method

11.28 _mysql_connector.MySQL.insert_id() Method

11.29 _mysql_connector.MySQL.more_results() Method

11.30 _mysql_connector.MySQL.next_result() Method

11.31 _mysql_connector.MySQL.num_fields() Method

11.32 _mysql_connector.MySQL.num_rows() Method

11.33 _mysql_connector.MySQL.ping() Method

11.34 _mysql_connector.MySQL.query() Method

11.35 _mysql_connector.MySQL.raw() Method

11.36 _mysql_connector.MySQL.refresh() Method

11.37 _mysql_connector.MySQL.rollback() Method

11.38 _mysql_connector.MySQL.select_db() Method

11.39 _mysql_connector.MySQL.set_character_set() Method

11.40 _mysql_connector.MySQL.shutdown() Method

11.41 _mysql_connector.MySQL.stat() Method

11.42 _mysql_connector.MySQL.thread_id() Method

11.43 _mysql_connector.MySQL.use_unicode() Method

11.44 _mysql_connector.MySQL.warning_count() Method

11.45 _mysql_connector.MySQL.have_result_set Property

This chapter contains the public API reference for the Connector/Python C Extension, also known as the _mysql_connector Python module.

The _mysql_connector C Extension module can be used directly without any other code of Connector/Python. One reason to use this module directly is for performance reasons.

Note

Examples in this reference use ccnx to represent a connector object as used with the _mysql_connector C Extension module. ccnx is an instance of the _mysql_connector.MySQL() class. It is distinct from the cnx object used in examples for the mysql.connector Connector/Python module described in Chapter 10, Connector/Python API Reference. cnx is an instance of the object returned by the connect() method of the MySQLConnection class.

Note

The C Extension is not part of the pure Python installation. It is an optional module that must be installed using a binary distribution of Connector/Python that includes it, or compiled using a source distribution. See Chapter 4, Connector/Python Installation.

11.1 _mysql_connector Module

The _mysql_connector module provides classes.

11.2 _mysql_connector.MySQL() Class

Syntax:

ccnx = _mysql_connector.MySQL(args)

The MySQL class is used to open and manage a connection to a MySQL server (referred to elsewhere in this reference as “the MySQL instance”). It is also used to send commands and SQL statements and read results.

The MySQL class wraps most functions found in the MySQL C Client API and adds some additional convenient functionality.

import _mysql_connector

ccnx = _mysql_connector.MySQL()
ccnx.connect(user='scott', password='tiger',
             host='127.0.0.1', database='employees')
ccnx.close()

Permitted arguments for the MySQL class are auth_plugin, buffered, charset_name, connection_timeout, raw, use_unicode. Those arguments correspond to the arguments of the same names for MySQLConnection.connect() as described at Section 7.1, “Connector/Python Connection Arguments”, except that charset_name corresponds to charset.

11.3 _mysql_connector.MySQL.affected_rows() Method

Syntax:

count = ccnx.afffected_rows()

Returns the number of rows changed, inserted, or deleted by the most recent UPDATE, INSERT, or DELETE statement.

11.4 _mysql_connector.MySQL.autocommit() Method

Syntax:

ccnx.autocommit(bool)

Sets the autocommit mode.

Raises a ValueError exception if mode is not True or False.

11.5 _mysql_connector.MySQL.buffered() Method

Syntax:

is_buffered = ccnx.buffered()     # getter
ccnx.buffered(bool)               # setter

With no argument, returns True or False to indicate whether the MySQL instance buffers (stores) the results.

With a boolean argument, sets the MySQL instance buffering mode.

For the setter syntax, raises a TypeError exception if the value is not True or False.

11.6 _mysql_connector.MySQL.change_user() Method

Syntax:

ccnx.change_user(user='user_name,
                 password='password_val',
                 database='db_name')

Changes the user and sets a new default database. Permitted arguments are user, password, and database.

11.7 _mysql_connector.MySQL.character_set_name() Method

Syntax:

charset = ccnx.character_set_name()

Returns the name of the default character set for the current MySQL session.

Some MySQL character sets have no equivalent names in Python. When this is the case, a name usable by Python is returned. For example, the 'utf8mb4' MySQL character set name is returned as 'utf8'.

11.8 _mysql_connector.MySQL.close() Method

Syntax:

ccnx.close()

Closes the MySQL connection.

11.9 _mysql_connector.MySQL.commit() Method

Syntax:

ccnx.commit()

Commits the current transaction.

11.10 _mysql_connector.MySQL.connect() Method

Syntax:

ccnx.connect(args)

Connects to a MySQL server.

import _mysql_connector

ccnx = _mysql_connector.MySQL()
ccnx.connect(user='scott', password='tiger',
             host='127.0.0.1', database='employees')
ccnx.close()

connect() supports the following arguments: host, user, password, database, port, unix_socket, client_flags, ssl_ca, ssl_cert, ssl_key, ssl_verify_cert, compress. See Section 7.1, “Connector/Python Connection Arguments”.

If ccnx is already connected, connect() discards any pending result set and closes the connection before reopening it.

Raises a TypeError exception if any argument is of an invalid type.

11.11 _mysql_connector.MySQL.connected() Method

Syntax:

is_connected = ccnx.connected()

Returns True or False to indicate whether the MySQL instance is connected.

11.12 _mysql_connector.MySQL.consume_result() Method

Syntax:

ccnx.consume_result()

Consumes the stored result set, if there is one, for this MySQL instance, by fetching all rows. If the statement that was executed returned multiple result sets, this method loops over and consumes all of them.

11.13 _mysql_connector.MySQL.convert_to_mysql() Method

Syntax:

converted_obj = ccnx.convert_to_mysql(obj))

Converts a Python object to a MySQL value based on the Python type of the object. The converted object is escaped and quoted.

ccnx.query('SELECT CURRENT_USER(), 1 + 3, NOW()')
row = ccnx.fetch_row()
for col in row:
  print(ccnx.convert_to_mysql(col))
ccnx.consume_result()

Raises a MySQLInterfaceError exception if the Python object cannot be converted.

11.14 _mysql_connector.MySQL.escape_string() Method

Syntax:

str = ccnx.escape_string(str_to_escape)

Uses the mysql_escape_string() C API function to create an SQL string that you can use in an SQL statement.

Raises a TypeError exception if the value does not have a Unicode, bytes, or (for Python 2) string type. Raises a MySQLError exception if the string could not be escaped.

11.15 _mysql_connector.MySQL.fetch_fields() Method

Syntax:

field_info = ccnx.fetch_fields()

Fetches column information for the active result set. Returns a list of tuples, one tuple per column

Raises a MySQLInterfaceError exception for any MySQL error returned by the MySQL server.

ccnx.query('SELECT CURRENT_USER(), 1 + 3, NOW()')
field_info = ccnx.fetch_fields()
for fi in field_info:
  print(fi)
ccnx.consume_result()

11.16 _mysql_connector.MySQL.fetch_row() Method

Syntax:

row = ccnx.fetch_row()

Fetches the next row from the active result set. The row is returned as a tuple that contains the values converted to Python objects, unless raw was set.

ccnx.query('SELECT CURRENT_USER(), 1 + 3, NOW()')
row = ccnx.fetch_row()
print(row)
ccnx.free_result()

Raises a MySQLInterfaceError exception for any MySQL error returned by the MySQL server.

11.17 _mysql_connector.MySQL.field_count() Method

Syntax:

count = ccnx.field_count()

Returns the number of columns in the active result set.

11.18 _mysql_connector.MySQL.free_result() Method

Syntax:

ccnx.free_result()

Frees the stored result set, if there is one, for this MySQL instance. If the statement that was executed returned multiple result sets, this method loops over and consumes all of them.

11.19 _mysql_connector.MySQL.get_character_set_info() Method

Syntax:

info = ccnx.get_character_set_info()

Returns information about the default character set for the current MySQL session. The returned dictionary has the keys number, name, csname, comment, dir, mbminlen, and mbmaxlen.

11.20 _mysql_connector.MySQL.get_client_info() Method

Syntax:

info = ccnx.get_client_info()

Returns the MySQL client library version as a string.

11.21 _mysql_connector.MySQL.get_client_version() Method

Syntax:

info = ccnx.get_client_version()

Returns the MySQL client library version as a tuple.

11.22 _mysql_connector.MySQL.get_host_info() Method

Syntax:

info = ccnx.get_host_info()

Returns a description of the type of connection in use as a string.

11.23 _mysql_connector.MySQL.get_proto_info() Method

Syntax:

info = ccnx.get_proto_info()

Returns the protocol version used by the current session.

11.24 _mysql_connector.MySQL.get_server_info() Method

Syntax:

info = ccnx.get_server_info()

Returns the MySQL server version as a string.

11.25 _mysql_connector.MySQL.get_server_version() Method

Syntax:

info = ccnx.get_server_version()

Returns the MySQL server version as a tuple.

11.26 _mysql_connector.MySQL.get_ssl_cipher() Method

Syntax:

info = ccnx.get_ssl_cipher()

Returns the SSL cipher used for the current session, or None if SSL is not in use.

11.27 _mysql_connector.MySQL.hex_string() Method

Syntax:

str = ccnx.hex_string(string_to_hexify)

Encodes a value in hexadecimal format and wraps it within X''. For example, "ham" becomes X'68616D'.

11.28 _mysql_connector.MySQL.insert_id() Method

Syntax:

insert_id = ccnx.insert_id()

Returns the AUTO_INCREMENT value generated by the most recent executed statement, or 0 if there is no such value.

11.29 _mysql_connector.MySQL.more_results() Method

Syntax:

more = ccnx.more_results()

Returns True or False to indicate whether any more result sets exist.

11.30 _mysql_connector.MySQL.next_result() Method

Syntax:

ccnx.next_result()

Initiates the next result set for a statement string that produced multiple result sets.

Raises a MySQLInterfaceError exception for any MySQL error returned by the MySQL server.

11.31 _mysql_connector.MySQL.num_fields() Method

Syntax:

count = ccnx.num_fields()

Returns the number of columns in the active result set.

11.32 _mysql_connector.MySQL.num_rows() Method

Syntax:

count = ccnx.num_rows()

Returns the number of rows in the active result set.

Raises a MySQLError exception if there is no result set.

11.33 _mysql_connector.MySQL.ping() Method

Syntax:

alive = ccnx.ping()

Returns True or False to indicate whether the connection to the MySQL server is working.

11.34 _mysql_connector.MySQL.query() Method

Syntax:

ccnx.query(args)

Executes an SQL statement. The permitted arguments are statement, buffered, raw, and raw_as_string.

ccnx.query('DROP TABLE IF EXISTS t')
ccnx.query('CREATE TABLE t (i INT NOT NULL AUTO_INCREMENT PRIMARY KEY)')
ccnx.query('INSERT INTO t (i) VALUES (NULL),(NULL),(NULL)')
ccnx.query('SELECT LAST_INSERT_ID()')
row = ccnx.fetch_row()
print('LAST_INSERT_ID(): ', row)
ccnx.consume_result()

buffered and raw, if not provided, take their values from the MySQL instance. raw_as_string is a special argument for Python v2 and returns str instead of bytearray (compatible with Connector/Python v1.x).

To check whether the query returns rows, check the have_result_set property of the MySQL instance.

query() returns True if the query executes, and raises an exception otherwise. It raises a TypeError exception if any argument has an invalid type, and a MySQLInterfaceError exception for any MySQL error returned by the MySQL server.

11.35 _mysql_connector.MySQL.raw() Method

Syntax:

is_raw = ccnx.raw()     # getter
ccnx.raw(bool)          # setter

With no argument, returns True or False to indicate whether the MySQL instance return the rows as is (without conversion to Python objects).

With a boolean argument, sets the MySQL instance raw mode.

11.36 _mysql_connector.MySQL.refresh() Method

Syntax:

ccnx.refresh(flags)

Flushes or resets the tables and caches indicated by the argument. The only argument currently permitted is an integer.

Raises a TypeError exception if the first argument is not an integer.

11.37 _mysql_connector.MySQL.rollback() Method

Syntax:

ccnx.rollback()

Rolls back the current transaction.

Raises a MySQLInterfaceError exception on errors.

11.38 _mysql_connector.MySQL.select_db() Method

Syntax:

ccnx.select_db(db_name)

Sets the default (current) database for the current session.

Raises a MySQLInterfaceError exception for any MySQL error returned by the MySQL server.

11.39 _mysql_connector.MySQL.set_character_set() Method

Syntax:

ccnx.set_character_set(charset_name)

Sets the default character set for the current session. The only argument permitted is a string that contains the character set name.

Raises a TypeError exception if the argument is not a PyString_type.

11.40 _mysql_connector.MySQL.shutdown() Method

Syntax:

ccnx.shutdown(flags)

Shuts down the MySQL server. The only argument currently permitted is an integer that describes the shutdown type.

Raises a TypeError exception if the first argument is not an integer. Raises a MySQLErrorInterface exception if an error is retured by the MySQL server.

11.41 _mysql_connector.MySQL.stat() Method

Syntax:

info = ccnx.stat()

Returns the server status as a string.

Raises a MySQLErrorInterface exception if an error is retured by the MySQL server.

11.42 _mysql_connector.MySQL.thread_id() Method

Syntax:

thread_id = ccnx.thread_id()

Returns the current thread or connection ID.

11.43 _mysql_connector.MySQL.use_unicode() Method

Syntax:

is_unicode = ccnx.use_unicode()      # getter
ccnx.use_unicode(bool)               # setter

With no argument, returns True or False to indicate whether the MySQL instance returns nonbinary strings as Unicode.

With a boolean argument, sets whether the MySQL instance returns nonbinary strings as Unicode.

11.44 _mysql_connector.MySQL.warning_count() Method

Syntax:

count = ccnx.warning_count()

Returns the number of errors, warnings, and notes produced by the previous SQL statement.

11.45 _mysql_connector.MySQL.have_result_set Property

Syntax:

has_rows = ccnx.have_result_set

After execution of the query() method, this property indicates whether the query returns rows.

Index

Symbols

_mysql_connector module, _mysql_connector Module

_mysql_connector.MySQL() class, _mysql_connector.MySQL() Class

_mysql_connector.MySQL.affected_rows() method, _mysql_connector.MySQL.affected_rows() Method

_mysql_connector.MySQL.autocommit() method, _mysql_connector.MySQL.autocommit() Method

_mysql_connector.MySQL.buffered() method, _mysql_connector.MySQL.buffered() Method

_mysql_connector.MySQL.change_user() method, _mysql_connector.MySQL.change_user() Method

_mysql_connector.MySQL.character_set_name() method, _mysql_connector.MySQL.character_set_name() Method

_mysql_connector.MySQL.close() method, _mysql_connector.MySQL.close() Method

_mysql_connector.MySQL.commit() method, _mysql_connector.MySQL.commit() Method

_mysql_connector.MySQL.connect() method, _mysql_connector.MySQL.connect() Method

_mysql_connector.MySQL.connected() method, _mysql_connector.MySQL.connected() Method

_mysql_connector.MySQL.consume_result() method, _mysql_connector.MySQL.consume_result() Method

_mysql_connector.MySQL.convert_to_mysql() method, _mysql_connector.MySQL.convert_to_mysql() Method

_mysql_connector.MySQL.escape_string() method, _mysql_connector.MySQL.escape_string() Method

_mysql_connector.MySQL.fetch_fields() method, _mysql_connector.MySQL.fetch_fields() Method

_mysql_connector.MySQL.fetch_row() method, _mysql_connector.MySQL.fetch_row() Method

_mysql_connector.MySQL.field_count() method, _mysql_connector.MySQL.field_count() Method

_mysql_connector.MySQL.free_result() method, _mysql_connector.MySQL.free_result() Method

_mysql_connector.MySQL.get_character_set_info() method, _mysql_connector.MySQL.get_character_set_info() Method

_mysql_connector.MySQL.get_client_info() method, _mysql_connector.MySQL.get_client_info() Method

_mysql_connector.MySQL.get_client_version() method, _mysql_connector.MySQL.get_client_version() Method

_mysql_connector.MySQL.get_host_info() method, _mysql_connector.MySQL.get_host_info() Method

_mysql_connector.MySQL.get_proto_info() method, _mysql_connector.MySQL.get_proto_info() Method

_mysql_connector.MySQL.get_server_info() method, _mysql_connector.MySQL.get_server_info() Method

_mysql_connector.MySQL.get_server_version() method, _mysql_connector.MySQL.get_server_version() Method

_mysql_connector.MySQL.get_ssl_cipher() method, _mysql_connector.MySQL.get_ssl_cipher() Method

_mysql_connector.MySQL.have_result_set property, _mysql_connector.MySQL.have_result_set Property

_mysql_connector.MySQL.hex_string() method, _mysql_connector.MySQL.hex_string() Method

_mysql_connector.MySQL.insert_id() method, _mysql_connector.MySQL.insert_id() Method

_mysql_connector.MySQL.more_results() method, _mysql_connector.MySQL.more_results() Method

_mysql_connector.MySQL.next_result() method, _mysql_connector.MySQL.next_result() Method

_mysql_connector.MySQL.num_fields() method, _mysql_connector.MySQL.num_fields() Method

_mysql_connector.MySQL.num_rows() method, _mysql_connector.MySQL.num_rows() Method

_mysql_connector.MySQL.ping() method, _mysql_connector.MySQL.ping() Method

_mysql_connector.MySQL.query() method, _mysql_connector.MySQL.query() Method

_mysql_connector.MySQL.raw() method, _mysql_connector.MySQL.raw() Method

_mysql_connector.MySQL.refresh() method, _mysql_connector.MySQL.refresh() Method

_mysql_connector.MySQL.rollback() method, _mysql_connector.MySQL.rollback() Method

_mysql_connector.MySQL.select_db() method, _mysql_connector.MySQL.select_db() Method

_mysql_connector.MySQL.set_character_set() method, _mysql_connector.MySQL.set_character_set() Method

_mysql_connector.MySQL.shutdown() method, _mysql_connector.MySQL.shutdown() Method

_mysql_connector.MySQL.stat() method, _mysql_connector.MySQL.stat() Method

_mysql_connector.MySQL.thread_id() method, _mysql_connector.MySQL.thread_id() Method

_mysql_connector.MySQL.use_unicode() method, _mysql_connector.MySQL.use_unicode() Method

_mysql_connector.MySQL.warning_count() method, _mysql_connector.MySQL.warning_count() Method

C

class

connection.MySQLConnection, connection.MySQLConnection Class

constants.CharacterSet, constants.CharacterSet Class

constants.ClientFlag, constants.ClientFlag Class

constants.FieldType, constants.FieldType Class

constants.RefreshOption, constants.RefreshOption Class

constants.SQLMode, constants.SQLMode Class

cursor.MySQLCursor, cursor.MySQLCursor Class

cursor.MySQLCursorBuffered, cursor.MySQLCursorBuffered Class

cursor.MySQLCursorBufferedDict, cursor.MySQLCursorBufferedDict Class

cursor.MySQLCursorBufferedNamedTuple, cursor.MySQLCursorBufferedNamedTuple Class

cursor.MySQLCursorBufferedRaw, cursor.MySQLCursorBufferedRaw Class

cursor.MySQLCursorDict, cursor.MySQLCursorDict Class

cursor.MySQLCursorNamedTuple, cursor.MySQLCursorNamedTuple Class

cursor.MySQLCursorPrepared, cursor.MySQLCursorPrepared Class

cursor.MySQLCursorRaw, cursor.MySQLCursorRaw Class

pooling.MySQLConnectionPool, pooling.MySQLConnectionPool Class

pooling.PooledMySQLConnection, pooling.PooledMySQLConnection Class

_mysql_connector.MySQL(), _mysql_connector.MySQL() Class

COM_STMT_SEND_LONG_DATA

prepared statements, cursor.MySQLCursorPrepared Class

connection.MySQLConnection class, connection.MySQLConnection Class

connection.MySQLConnection() constructor, connection.MySQLConnection() Constructor

Connector/Python, Introduction to MySQL Connector/Python

constants.CharacterSet class, constants.CharacterSet Class

constants.ClientFlag class, constants.ClientFlag Class

constants.FieldType class, constants.FieldType Class

constants.RefreshOption class, constants.RefreshOption Class

constants.SQLMode class, constants.SQLMode Class

constructor

connection.MySQLConnection(), connection.MySQLConnection() Constructor

cursor.MySQLCursor, cursor.MySQLCursor Constructor

pooling.MySQLConnectionPool, pooling.MySQLConnectionPool Constructor

pooling.PooledMySQLConnection, pooling.PooledMySQLConnection Constructor

cursor.mysqlcursor

Subclasses, Subclasses cursor.MySQLCursor

cursor.MySQLCursor class, cursor.MySQLCursor Class

cursor.MySQLCursor constructor, cursor.MySQLCursor Constructor

cursor.MySQLCursorBuffered class, cursor.MySQLCursorBuffered Class

cursor.MySQLCursorBufferedDict class, cursor.MySQLCursorBufferedDict Class

cursor.MySQLCursorBufferedNamedTuple class, cursor.MySQLCursorBufferedNamedTuple Class

cursor.MySQLCursorBufferedRaw class, cursor.MySQLCursorBufferedRaw Class

cursor.MySQLCursorDict class, cursor.MySQLCursorDict Class

cursor.MySQLCursorNamedTuple class, cursor.MySQLCursorNamedTuple Class

cursor.MySQLCursorPrepared class, cursor.MySQLCursorPrepared Class

cursor.MySQLCursorRaw class, cursor.MySQLCursorRaw Class

D

DYLD_LIBRARY_PATH environment variable, Application Development with the Connector/Python C Extension

E

environment variable

DYLD_LIBRARY_PATH, Application Development with the Connector/Python C Extension

errorcode module, errorcode Module

errors.custom_error_exception() function, errors.custom_error_exception() Function

errors.DatabaseError exception, errors.DatabaseError Exception

errors.DataError exception, errors.DataError Exception

errors.Error exception, errors.Error Exception

errors.IntegrityError exception, errors.IntegrityError Exception

errors.InterfaceError exception, errors.InterfaceError Exception

errors.InternalError exception, errors.InternalError Exception

errors.NotSupportedError exception, errors.NotSupportedError Exception

errors.OperationalError exception, errors.OperationalError Exception

errors.PoolError exception, errors.PoolError Exception

errors.ProgrammingError exception, errors.ProgrammingError Exception

errors.Warning exception, errors.Warning Exception

exception

errors.DatabaseError, errors.DatabaseError Exception

errors.DataError, errors.DataError Exception

errors.Error, errors.Error Exception

errors.IntegrityError, errors.IntegrityError Exception

errors.InterfaceError, errors.InterfaceError Exception

errors.InternalError, errors.InternalError Exception

errors.NotSupportedError, errors.NotSupportedError Exception

errors.OperationalError, errors.OperationalError Exception

errors.PoolError, errors.PoolError Exception

errors.ProgrammingError, errors.ProgrammingError Exception

errors.Warning, errors.Warning Exception

F

function

errors.custom_error_exception(), errors.custom_error_exception() Function

M

method

mysql.connector.connect(), mysql.connector.connect() Method

MySQLConnection.close(), MySQLConnection.close() Method

MySQLConnection.cmd_change_user(), MySQLConnection.cmd_change_user() Method

MySQLConnection.cmd_debug(), MySQLConnection.cmd_debug() Method

MySQLConnection.cmd_init_db(), MySQLConnection.cmd_init_db() Method

MySQLConnection.cmd_ping(), MySQLConnection.cmd_ping() Method

MySQLConnection.cmd_process_info(), MySQLConnection.cmd_process_info() Method

MySQLConnection.cmd_process_kill(), MySQLConnection.cmd_process_kill() Method

MySQLConnection.cmd_query(), MySQLConnection.cmd_query() Method

MySQLConnection.cmd_query_iter(), MySQLConnection.cmd_query_iter() Method

MySQLConnection.cmd_quit(), MySQLConnection.cmd_quit() Method

MySQLConnection.cmd_refresh(), MySQLConnection.cmd_refresh() Method

MySQLConnection.cmd_reset_connection(), MySQLConnection.cmd_reset_connection() Method

MySQLConnection.cmd_shutdown(), MySQLConnection.cmd_shutdown() Method

MySQLConnection.cmd_statistics(), MySQLConnection.cmd_statistics() Method

MySQLConnection.commit(), MySQLConnection.commit() Method

MySQLConnection.config(), MySQLConnection.config() Method

MySQLConnection.connect(), MySQLConnection.connect() Method

MySQLConnection.cursor(), MySQLConnection.cursor() Method

MySQLConnection.disconnect(), MySQLConnection.disconnect() Method

MySQLConnection.get_row(), MySQLConnection.get_row() Method

MySQLConnection.get_rows(), MySQLConnection.get_rows() Method

MySQLConnection.get_server_info(), MySQLConnection.get_server_info() Method

MySQLConnection.get_server_version(), MySQLConnection.get_server_version() Method

MySQLConnection.isset_client_flag(), MySQLConnection.isset_client_flag() Method

MySQLConnection.is_connected(), MySQLConnection.is_connected() Method

MySQLConnection.ping(), MySQLConnection.ping() Method

MySQLConnection.reconnect(), MySQLConnection.reconnect() Method

MySQLConnection.reset_session(), MySQLConnection.reset_session() Method

MySQLConnection.rollback(), MySQLConnection.rollback() Method

MySQLConnection.set_charset_collation(), MySQLConnection.set_charset_collation() Method

MySQLConnection.set_client_flags(), MySQLConnection.set_client_flags() Method

MySQLConnection.shutdown(), MySQLConnection.shutdown() Method

MySQLConnection.start_transaction(), MySQLConnection.start_transaction() Method

MySQLConnectionPool.add_connection(), MySQLConnectionPool.add_connection() Method

MySQLConnectionPool.get_connection(), MySQLConnectionPool.get_connection() Method

MySQLConnectionPool.set_config(), MySQLConnectionPool.set_config() Method

MySQLCursor.callproc(), MySQLCursor.callproc() Method

MySQLCursor.close(), MySQLCursor.close() Method

MySQLCursor.execute(), MySQLCursor.execute() Method

MySQLCursor.executemany(), MySQLCursor.executemany() Method

MySQLCursor.fetchall(), MySQLCursor.fetchall() Method

MySQLCursor.fetchmany(), MySQLCursor.fetchmany() Method

MySQLCursor.fetchone(), MySQLCursor.fetchone() Method

MySQLCursor.fetchwarnings(), MySQLCursor.fetchwarnings() Method

MySQLCursor.stored_results(), MySQLCursor.stored_results() Method

PooledMySQLConnection.close(), PooledMySQLConnection.close() Method

PooledMySQLConnection.config(), PooledMySQLConnection.config() Method

_mysql_connector.MySQL.affected_rows(), _mysql_connector.MySQL.affected_rows() Method

_mysql_connector.MySQL.autocommit(), _mysql_connector.MySQL.autocommit() Method

_mysql_connector.MySQL.buffered(), _mysql_connector.MySQL.buffered() Method

_mysql_connector.MySQL.change_user(), _mysql_connector.MySQL.change_user() Method

_mysql_connector.MySQL.character_set_name(), _mysql_connector.MySQL.character_set_name() Method

_mysql_connector.MySQL.close(), _mysql_connector.MySQL.close() Method

_mysql_connector.MySQL.commit(), _mysql_connector.MySQL.commit() Method

_mysql_connector.MySQL.connect(), _mysql_connector.MySQL.connect() Method

_mysql_connector.MySQL.connected(), _mysql_connector.MySQL.connected() Method

_mysql_connector.MySQL.consume_result(), _mysql_connector.MySQL.consume_result() Method

_mysql_connector.MySQL.convert_to_mysql(), _mysql_connector.MySQL.convert_to_mysql() Method

_mysql_connector.MySQL.escape_string(), _mysql_connector.MySQL.escape_string() Method

_mysql_connector.MySQL.fetch_fields(), _mysql_connector.MySQL.fetch_fields() Method

_mysql_connector.MySQL.fetch_row(), _mysql_connector.MySQL.fetch_row() Method

_mysql_connector.MySQL.field_count(), _mysql_connector.MySQL.field_count() Method

_mysql_connector.MySQL.free_result(), _mysql_connector.MySQL.free_result() Method

_mysql_connector.MySQL.get_character_set_info(), _mysql_connector.MySQL.get_character_set_info() Method

_mysql_connector.MySQL.get_client_info(), _mysql_connector.MySQL.get_client_info() Method

_mysql_connector.MySQL.get_client_version(), _mysql_connector.MySQL.get_client_version() Method

_mysql_connector.MySQL.get_host_info(), _mysql_connector.MySQL.get_host_info() Method

_mysql_connector.MySQL.get_proto_info(), _mysql_connector.MySQL.get_proto_info() Method

_mysql_connector.MySQL.get_server_info(), _mysql_connector.MySQL.get_server_info() Method

_mysql_connector.MySQL.get_server_version(), _mysql_connector.MySQL.get_server_version() Method

_mysql_connector.MySQL.get_ssl_cipher(), _mysql_connector.MySQL.get_ssl_cipher() Method

_mysql_connector.MySQL.hex_string(), _mysql_connector.MySQL.hex_string() Method

_mysql_connector.MySQL.insert_id(), _mysql_connector.MySQL.insert_id() Method

_mysql_connector.MySQL.more_results(), _mysql_connector.MySQL.more_results() Method

_mysql_connector.MySQL.next_result(), _mysql_connector.MySQL.next_result() Method

_mysql_connector.MySQL.num_fields(), _mysql_connector.MySQL.num_fields() Method

_mysql_connector.MySQL.num_rows(), _mysql_connector.MySQL.num_rows() Method

_mysql_connector.MySQL.ping(), _mysql_connector.MySQL.ping() Method

_mysql_connector.MySQL.query(), _mysql_connector.MySQL.query() Method

_mysql_connector.MySQL.raw(), _mysql_connector.MySQL.raw() Method

_mysql_connector.MySQL.refresh(), _mysql_connector.MySQL.refresh() Method

_mysql_connector.MySQL.rollback(), _mysql_connector.MySQL.rollback() Method

_mysql_connector.MySQL.select_db(), _mysql_connector.MySQL.select_db() Method

_mysql_connector.MySQL.set_character_set(), _mysql_connector.MySQL.set_character_set() Method

_mysql_connector.MySQL.shutdown(), _mysql_connector.MySQL.shutdown() Method

_mysql_connector.MySQL.stat(), _mysql_connector.MySQL.stat() Method

_mysql_connector.MySQL.thread_id(), _mysql_connector.MySQL.thread_id() Method

_mysql_connector.MySQL.use_unicode(), _mysql_connector.MySQL.use_unicode() Method

_mysql_connector.MySQL.warning_count(), _mysql_connector.MySQL.warning_count() Method

module

errorcode, errorcode Module

mysql.connector, mysql.connector Module

_mysql_connector, _mysql_connector Module

mysql.connector module, mysql.connector Module

mysql.connector.apilevel property, mysql.connector.apilevel Property

mysql.connector.connect() method, mysql.connector.connect() Method

mysql.connector.paramstyle property, mysql.connector.paramstyle Property

mysql.connector.threadsafety property, mysql.connector.threadsafety Property

mysql.connector.__version_info__ property, mysql.connector.__version_info__ Property

mysql.connector.__version__ property, mysql.connector.__version__ Property

MySQLConnection.autocommit property, MySQLConnection.autocommit Property

MySQLConnection.can_consume_results property, MySQLConnection.can_consume_results Property

MySQLConnection.charset property, MySQLConnection.charset Property

MySQLConnection.close() method, MySQLConnection.close() Method

MySQLConnection.cmd_change_user() method, MySQLConnection.cmd_change_user() Method

MySQLConnection.cmd_debug() method, MySQLConnection.cmd_debug() Method

MySQLConnection.cmd_init_db() method, MySQLConnection.cmd_init_db() Method

MySQLConnection.cmd_ping() method, MySQLConnection.cmd_ping() Method

MySQLConnection.cmd_process_info() method, MySQLConnection.cmd_process_info() Method

MySQLConnection.cmd_process_kill() method, MySQLConnection.cmd_process_kill() Method

MySQLConnection.cmd_query() method, MySQLConnection.cmd_query() Method

MySQLConnection.cmd_query_iter() method, MySQLConnection.cmd_query_iter() Method

MySQLConnection.cmd_quit() method, MySQLConnection.cmd_quit() Method

MySQLConnection.cmd_refresh() method, MySQLConnection.cmd_refresh() Method

MySQLConnection.cmd_reset_connection() method, MySQLConnection.cmd_reset_connection() Method

MySQLConnection.cmd_shutdown() method, MySQLConnection.cmd_shutdown() Method

MySQLConnection.cmd_statistics() method, MySQLConnection.cmd_statistics() Method

MySQLConnection.collation property, MySQLConnection.collation Property

MySQLConnection.commit() method, MySQLConnection.commit() Method

MySQLConnection.config() method, MySQLConnection.config() Method

MySQLConnection.connect() method, MySQLConnection.connect() Method

MySQLConnection.connection_id property, MySQLConnection.connection_id Property

MySQLConnection.cursor() method, MySQLConnection.cursor() Method

MySQLConnection.database property, MySQLConnection.database Property

MySQLConnection.disconnect() method, MySQLConnection.disconnect() Method

MySQLConnection.get_row() method, MySQLConnection.get_row() Method

MySQLConnection.get_rows() method, MySQLConnection.get_rows() Method

MySQLConnection.get_server_info() method, MySQLConnection.get_server_info() Method

MySQLConnection.get_server_version() method, MySQLConnection.get_server_version() Method

MySQLConnection.get_warnings property, MySQLConnection.get_warnings Property

MySQLConnection.in_transaction property, MySQLConnection.in_transaction Property

MySQLConnection.isset_client_flag() method, MySQLConnection.isset_client_flag() Method

MySQLConnection.is_connected() method, MySQLConnection.is_connected() Method

MySQLConnection.ping() method, MySQLConnection.ping() Method

MySQLConnection.raise_on_warnings property, MySQLConnection.raise_on_warnings Property

MySQLConnection.reconnect() method, MySQLConnection.reconnect() Method

MySQLConnection.reset_session() method, MySQLConnection.reset_session() Method

MySQLConnection.rollback() method, MySQLConnection.rollback() Method

MySQLConnection.server_host property, MySQLConnection.server_host Property

MySQLConnection.server_port property, MySQLConnection.server_port Property

MySQLConnection.set_charset_collation() method, MySQLConnection.set_charset_collation() Method

MySQLConnection.set_client_flags() method, MySQLConnection.set_client_flags() Method

MySQLConnection.shutdown() method, MySQLConnection.shutdown() Method

MySQLConnection.sql_mode property, MySQLConnection.sql_mode Property

MySQLConnection.start_transaction() method, MySQLConnection.start_transaction() Method

MySQLConnection.time_zone property, MySQLConnection.time_zone Property

MySQLConnection.unix_socket property, MySQLConnection.unix_socket Property

MySQLConnection.user property, MySQLConnection.user Property

MySQLConnectionPool.add_connection() method, MySQLConnectionPool.add_connection() Method

MySQLConnectionPool.get_connection() method, MySQLConnectionPool.get_connection() Method

MySQLConnectionPool.pool_name property, MySQLConnectionPool.pool_name Property

MySQLConnectionPool.set_config() method, MySQLConnectionPool.set_config() Method

MySQLCursor.callproc() method, MySQLCursor.callproc() Method

MySQLCursor.close() method, MySQLCursor.close() Method

MySQLCursor.column_names property, MySQLCursor.column_names Property

MySQLCursor.description property, MySQLCursor.description Property

MySQLCursor.execute() method, MySQLCursor.execute() Method

MySQLCursor.executemany() method, MySQLCursor.executemany() Method

MySQLCursor.fetchall() method, MySQLCursor.fetchall() Method

MySQLCursor.fetchmany() method, MySQLCursor.fetchmany() Method

MySQLCursor.fetchone() method, MySQLCursor.fetchone() Method

MySQLCursor.fetchwarnings() method, MySQLCursor.fetchwarnings() Method

MySQLCursor.lastrowid property, MySQLCursor.lastrowid Property

MySQLCursor.rowcount property, MySQLCursor.rowcount Property

MySQLCursor.statement property, MySQLCursor.statement Property

MySQLCursor.stored_results() method, MySQLCursor.stored_results() Method

MySQLCursor.with_rows property, MySQLCursor.with_rows Property

P

PEP 249, Introduction to MySQL Connector/Python

PooledMySQLConnection.close() method, PooledMySQLConnection.close() Method

PooledMySQLConnection.config() method, PooledMySQLConnection.config() Method

PooledMySQLConnection.pool_name property, PooledMySQLConnection.pool_name Property

pooling.MySQLConnectionPool class, pooling.MySQLConnectionPool Class

pooling.MySQLConnectionPool constructor, pooling.MySQLConnectionPool Constructor

pooling.PooledMySQLConnection class, pooling.PooledMySQLConnection Class

pooling.PooledMySQLConnection constructor, pooling.PooledMySQLConnection Constructor

prepared statements, cursor.MySQLCursorPrepared Class

property

mysql.connector.apilevel, mysql.connector.apilevel Property

mysql.connector.paramstyle, mysql.connector.paramstyle Property

mysql.connector.threadsafety, mysql.connector.threadsafety Property

mysql.connector.__version_info__, mysql.connector.__version_info__ Property

mysql.connector.__version__, mysql.connector.__version__ Property

MySQLConnection.autocommit, MySQLConnection.autocommit Property

MySQLConnection.can_consume_results, MySQLConnection.can_consume_results Property

MySQLConnection.charset, MySQLConnection.charset Property

MySQLConnection.collation, MySQLConnection.collation Property

MySQLConnection.connection_id, MySQLConnection.connection_id Property

MySQLConnection.database, MySQLConnection.database Property

MySQLConnection.get_warnings, MySQLConnection.get_warnings Property

MySQLConnection.in_transaction, MySQLConnection.in_transaction Property

MySQLConnection.raise_on_warnings, MySQLConnection.raise_on_warnings Property

MySQLConnection.server_host, MySQLConnection.server_host Property

MySQLConnection.server_port, MySQLConnection.server_port Property

MySQLConnection.sql_mode, MySQLConnection.sql_mode Property

MySQLConnection.time_zone, MySQLConnection.time_zone Property

MySQLConnection.unix_socket, MySQLConnection.unix_socket Property

MySQLConnection.user, MySQLConnection.user Property

MySQLConnectionPool.pool_name, MySQLConnectionPool.pool_name Property

MySQLCursor.column_names, MySQLCursor.column_names Property

MySQLCursor.description, MySQLCursor.description Property

MySQLCursor.lastrowid, MySQLCursor.lastrowid Property

MySQLCursor.rowcount, MySQLCursor.rowcount Property

MySQLCursor.statement, MySQLCursor.statement Property

MySQLCursor.with_rows, MySQLCursor.with_rows Property

PooledMySQLConnection.pool_name, PooledMySQLConnection.pool_name Property

_mysql_connector.MySQL.have_result_set, _mysql_connector.MySQL.have_result_set Property

Python, Introduction to MySQL Connector/Python

Python Database API Specification v2.0 (PEP 249), Introduction to MySQL Connector/Python

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Subclasses cursor.mysqlcursor, Subclasses cursor.MySQLCursor