Welcome to PyMySQL’s documentation!

User Guide

The PyMySQL user guide explains how to install PyMySQL and how to contribute to the library as a developer.

Installation

The last stable release is available on PyPI and can be installed with pip:

$ pip install PyMySQL

Requirements

  • Python – one of the following:
  • MySQL Server – one of the following:

Examples

CRUD

The following examples make use of a simple table

CREATE TABLE `users` (
    `id` int(11) NOT NULL AUTO_INCREMENT,
    `email` varchar(255) COLLATE utf8_bin NOT NULL,
    `password` varchar(255) COLLATE utf8_bin NOT NULL,
    PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin
AUTO_INCREMENT=1 ;

import pymysql.cursors

# Connect to the database
connection = pymysql.connect(host='localhost',
                             user='user',
                             password='passwd',
                             db='db',
                             charset='utf8mb4',
                             cursorclass=pymysql.cursors.DictCursor)

try:
    with connection.cursor() as cursor:
        # Create a new record
        sql = "INSERT INTO `users` (`email`, `password`) VALUES (%s, %s)"
        cursor.execute(sql, ('webmaster@python.org', 'very-secret'))

    # connection is not autocommit by default. So you must commit to save
    # your changes.
    connection.commit()

    with connection.cursor() as cursor:
        # Read a single record
        sql = "SELECT `id`, `password` FROM `users` WHERE `email`=%s"
        cursor.execute(sql, ('webmaster@python.org',))
        result = cursor.fetchone()
        print(result)
finally:
    connection.close()

This example will print:

{'password': 'very-secret', 'id': 1}

Development

You can help developing PyMySQL by contributing on GitHub.

Building the documentation

Go to the docs directory and run make html.

Test Suite

If you would like to run the test suite, create a database for testing like this:

mysql -e 'create database test_pymysql  DEFAULT CHARACTER SET utf8 DEFAULT COLLATE utf8_general_ci;'
mysql -e 'create database test_pymysql2 DEFAULT CHARACTER SET utf8 DEFAULT COLLATE utf8_general_ci;'

Then, copy the file .travis/database.json to pymysql/tests/databases.json and edit the new file to match your MySQL configuration:

$ cp .travis/database.json pymysql/tests/databases.json
$ $EDITOR pymysql/tests/databases.json

To run all the tests, execute the script runtests.py:

$ python runtests.py

A tox.ini file is also provided for conveniently running tests on multiple Python versions:

$ tox

API Reference

If you are looking for information on a specific function, class or method, this part of the documentation is for you.

For more information, please read the Python Database API specification.

Connection Object

class pymysql.connections.Connection(host=None, user=None, password='', database=None, port=0, unix_socket=None, charset='', sql_mode=None, read_default_file=None, conv=None, use_unicode=None, client_flag=0, cursorclass=<class 'pymysql.cursors.Cursor'>, init_command=None, connect_timeout=10, ssl=None, read_default_group=None, compress=None, named_pipe=None, no_delay=None, autocommit=False, db=None, passwd=None, local_infile=False, max_allowed_packet=16777216, defer_connect=False, auth_plugin_map={}, read_timeout=None, write_timeout=None, bind_address=None, binary_prefix=False)

Representation of a socket with a mysql server.

The proper way to get an instance of this class is to call connect().

Establish a connection to the MySQL database. Accepts several arguments:

Parameters:
  • host – Host where the database server is located
  • user – Username to log in as
  • password – Password to use.
  • database – Database to use, None to not use a particular one.
  • port – MySQL port to use, default is usually OK. (default: 3306)
  • bind_address – When the client has multiple network interfaces, specify the interface from which to connect to the host. Argument can be a hostname or an IP address.
  • unix_socket – Optionally, you can use a unix socket rather than TCP/IP.
  • charset – Charset you want to use.
  • sql_mode – Default SQL_MODE to use.
  • read_default_file – Specifies my.cnf file to read these parameters from under the [client] section.
  • conv – Conversion dictionary to use instead of the default one. This is used to provide custom marshalling and unmarshaling of types. See converters.
  • use_unicode – Whether or not to default to unicode strings. This option defaults to true for Py3k.
  • client_flag – Custom flags to send to MySQL. Find potential values in constants.CLIENT.
  • cursorclass – Custom cursor class to use.
  • init_command – Initial SQL statement to run when connection is established.
  • connect_timeout – Timeout before throwing an exception when connecting. (default: 10, min: 1, max: 31536000)
  • ssl – A dict of arguments similar to mysql_ssl_set()’s parameters. For now the capath and cipher arguments are not supported.
  • read_default_group – Group to read from in the configuration file.
  • compress – Not supported
  • named_pipe – Not supported
  • autocommit – Autocommit mode. None means use server default. (default: False)
  • local_infile – Boolean to enable the use of LOAD DATA LOCAL command. (default: False)
  • max_allowed_packet – Max size of packet sent to server in bytes. (default: 16MB) Only used to limit size of “LOAD LOCAL INFILE” data packet smaller than default (16KB).
  • defer_connect – Don’t explicitly connect on contruction - wait for connect call. (default: False)
  • auth_plugin_map – A dict of plugin names to a class that processes that plugin. The class will take the Connection object as the argument to the constructor. The class needs an authenticate method taking an authentication packet as an argument. For the dialog plugin, a prompt(echo, prompt) method can be used (if no authenticate method) for returning a string from the user. (experimental)
  • db – Alias for database. (for compatibility to MySQLdb)
  • passwd – Alias for password. (for compatibility to MySQLdb)
  • binary_prefix – Add _binary prefix on bytes and bytearray. (default: False)
autocommit_mode = None

specified autocommit mode. None means use server default.

begin()

Begin transaction.

close()

Send the quit message and close the socket

commit()

Commit changes to stable storage

cursor(cursor=None)

Create a new cursor to execute queries with

ping(reconnect=True)

Check if the server is alive

rollback()

Roll back the current transaction

select_db(db)

Set current db

show_warnings()

SHOW WARNINGS

Cursor Objects

class pymysql.cursors.Cursor(connection)

This is the object you use to interact with the database.

Do not create an instance of a Cursor yourself. Call connections.Connection.cursor().

callproc(procname, args=())

Execute stored procedure procname with args

procname – string, name of procedure to execute on server

args – Sequence of parameters to use with procedure

Returns the original args.

Compatibility warning: PEP-249 specifies that any modified parameters must be returned. This is currently impossible as they are only available by storing them in a server variable and then retrieved by a query. Since stored procedures return zero or more result sets, there is no reliable way to get at OUT or INOUT parameters via callproc. The server variables are named @_procname_n, where procname is the parameter above and n is the position of the parameter (from zero). Once all result sets generated by the procedure have been fetched, you can issue a SELECT @_procname_0, … query using .execute() to get any OUT or INOUT values.

Compatibility warning: The act of calling a stored procedure itself creates an empty result set. This appears after any result sets generated by the procedure. This is non-standard behavior with respect to the DB-API. Be sure to use nextset() to advance through all result sets; otherwise you may get disconnected.

close()

Closing a cursor just exhausts all remaining data.

execute(query, args=None)

Execute a query

Parameters:
  • query (str) – Query to execute.
  • args (tuple, list or dict) – parameters used with query. (optional)
Returns:

Number of affected rows
Return type:

int

If args is a list or tuple, %s can be used as a placeholder in the query. If args is a dict, %(name)s can be used as a placeholder in the query.

executemany(query, args)

Run several data against one query

Parameters:
  • query – query to execute on server
  • args – Sequence of sequences or mappings. It is used as parameter.
Returns:

Number of rows affected, if any.

This method improves performance on multiple-row INSERT and REPLACE. Otherwise it is equivalent to looping over args with execute().

fetchall()

Fetch all the rows

fetchmany(size=None)

Fetch several rows

fetchone()

Fetch the next row

max_stmt_length = 1024000

Max statement size which executemany() generates.

Max size of allowed statement is max_allowed_packet - packet_header_size. Default value of max_allowed_packet is 1048576.

mogrify(query, args=None)

Returns the exact string that is sent to the database by calling the execute() method.

This method follows the extension to the DB API 2.0 followed by Psycopg.

setinputsizes(*args)

Does nothing, required by DB API.

setoutputsizes(*args)

Does nothing, required by DB API.

class pymysql.cursors.SSCursor(connection)

Unbuffered Cursor, mainly useful for queries that return a lot of data, or for connections to remote servers over a slow network.

Instead of copying every row of data into a buffer, this will fetch rows as needed. The upside of this is the client uses much less memory, and rows are returned much faster when traveling over a slow network or if the result set is very big.

There are limitations, though. The MySQL protocol doesn’t support returning the total number of rows, so the only way to tell how many rows there are is to iterate over every row returned. Also, it currently isn’t possible to scroll backwards, as only the current row is held in memory.

fetchall()

Fetch all, as per MySQLdb. Pretty useless for large queries, as it is buffered. See fetchall_unbuffered(), if you want an unbuffered generator version of this method.

fetchall_unbuffered()

Fetch all, implemented as a generator, which isn’t to standard, however, it doesn’t make sense to return everything in a list, as that would use ridiculous memory for large result sets.

fetchmany(size=None)

Fetch many

fetchone()

Fetch next row

read_next()

Read next row

class pymysql.cursors.DictCursor(connection)

A cursor which returns results as a dictionary

class pymysql.cursors.SSDictCursor(connection)

An unbuffered cursor, which returns results as a dictionary

Indices and tables