Connect From Python App

Overview

Python developers can use MariaDB Connector/Python to establish client connections with MariaDB Cloud.

Connections

Connections are managed using the following Python class:

Class	Description
Connection	Represents a connection to SkySQL.

Connections are created, used, and managed using the following Connection class functions:

Function	Description
connect()	Establishes a connection to a database server and returns a connection object.
cursor()	Returns a new cursor object for the current connection.
change_user()	Changes the user and default database of the current connection.
reconnect()	Tries to make a connection object active again by reconnecting to the server using the same credentials which were specified in connect() method.
close()	Closes the connection.

Determine the connection information for your MariaDB Cloud database service:

connect() parameter	Where to find it
user	Default username in the Service Credentials view, or the username you created
passwd	Default password in the Service Credentials view, the password you set on the default user, or the password for the user you created
host	Fully Qualified Domain Name in the Connection Parameters Portal
ssl_verify_cert	Set to True to support SSL
port	Read-Write Port or Read-Only Port in the Connection Parameters Portal

Code Example: Connecting

The following code example connects to an example server.

Examples:

# Module Import
import mariadb
import sys

# Instantiate Connection
try:
   conn = mariadb.connect(
      host="192.0.2.1",
      port=3306,
      user="db_user",
      password="USER_PASSWORD")
except mariadb.Error as e:
   print(f"Error connecting to the database: {e}")
   sys.exit(1)

# Use Connection
# ...

# Close Connection
conn.close()

# Module Import
import mariadb
import sys

# Instantiate Connection
try:
   conn = mariadb.connect(
      host="SKYSQL_SERVICE.mdb0000001.db.skysql.com",
      port=5009,
      ssl_verify_cert=True,
      user="DB00000001",
      password="USER_PASSWORD")
except mariadb.Error as e:
   print(f"Error connecting to the database: {e}")
   sys.exit(1)

# Use Connection
# ...

# Close Connection
conn.close()

• The connect() function returns an instance of the Connection class, which is assigned to the conn variable.

• The connection attributes are passed as keyword arguments to theconnect()function.

• When you are done with a connection, close it to free resources. Close the connection using the close()method.

Multiple Connections

Instantiating the Connection class creates a single connection to MariaDB database products. Applications that require multiple connections may benefit from pooling connections.

Close a Connection

MariaDB Connector/Python closes the connection as part of the class's destructor, which is executed when an instance of the class goes out of scope. This can happen in many cases, such as:

• When the program exits

• When the instance of the Connection class is defined in the local scope of a function, and the function returns

• When the instance of the Connection class is defined as an attribute of a custom class's instance, and the custom class's instance goes out of scope.

Connections can also be explicitly closed using the close() method, which is helpful when the connection is no longer needed, but the variable is still in scope.

Connection Failover

Starting with MariaDB Connector/Python 1.1 when MariaDB Connector/Python is built with MariaDB Connector/C 3.3, the connector supports connection failover when auto_reconnect is enabled and the connection string contains a comma-separated list of multiple server addresses.

To enable connection failover:

• Call the mariadb.connect function with the host argument specified as a comma-separated list containing multiple server addresses. The connector attempts to connect to the addresses in the order specified in the list.

• Set auto_reconnect to True. If the connection fails, the connector will attempt to reconnect to the addresses in the order specified in the list.

The following code example connects with connection failover enabled:

# Module Import
import mariadb
import sys

# Instantiate Connection
try:
   conn = mariadb.connect(
      host="192.0.2.1,192.0.2.0,198.51.100.0",
      port=3306,
      user="db_user",
      password="USER_PASSWORD")
   conn.auto_reconnect = True
except mariadb.Error as e:
   print(f"Error connecting to the database: {e}")
   sys.exit(1)

# Use Connection
# ...

# Close Connection
conn.close()

# Module Import
import mariadb
import sys

# Instantiate Connection
try:
   conn = mariadb.connect(
      host="SKYSQL_SERVICE.mdb0000001.db.skysql.com,SKYSQL_SERVICE.mdb0000002.db.skysql.com",
      port=5009,
      ssl_verify_cert=True,
      user="DB00000001",
      password="USER_PASSWORD")
   conn.auto_reconnect = True
except mariadb.Error as e:
   print(f"Error connecting to the database: {e}")
   sys.exit(1)

# Use Connection
# ...

# Close Connection
conn.close()