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22.6.6. 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 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 22.33. 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.
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.
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 suchcases.
dsn Not supported (raises NotSupportedError when used).

MySQL Authentication

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 parameter 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.

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 Section 5.1.7, "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 ClientFlagprint '\n'.join(ClientFlag.get_full_info())

If client_flags is not specified (that is, it is zero), defaults are used for MySQL v4.1 and later. 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)

Buffering for Result Sets

By default, MySQL Connector/Python does not buffer or pre-fetch 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 22.6.7.3.6, "Method MySQLConnection.cursor(buffered=None, raw=None, cursor_class=None)").

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 parameter 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 arguments, 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 argument set to True.

# 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-cert.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() 

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.