Installation guide

6. mxODBC Connection Objects

The DriverConnect() API is only available if the ODBC driver or ODBC

driver manager supports this. It is available on all supported ODBC driver

manager subpackages such as the one for Windows and

iODBC/unixODBC/DataDirect on Unix platforms. See the subpackages section

for details.

ODBC(dsn, user='', password='', clear_auto_commit=1,

errorhandler=None)

Is just an alias for Connect() needed for Python DB API 1.0 compliance.

6.4 Default Transaction Settings

ODBC usually defaults to auto-commit, meaning that all actions on the

connection are directly applied to the database. Since this can be dangerous,

mxODBC defaults to turning auto-commit off at connection initiation time

provided the database supports transactions.

All connection constructors implicitly start a new transaction when connecting to

a database in transactional mode.

When connecting to a database with transaction support, you should explicitly do

.rollback() or .commit() prior to closing the connection. mxODBC does an

automatic rollback of the transaction when the connection is closed if the driver

supports transactions.

6.4.1 Overriding the Default

The value of the clear_auto_commit connection parameter overrides this default

behavior. Passing a

0 as value disables the clearing of the auto-commit flag and

lets the connection use the database's default commit behavior. Please see the

database documentation for details on its default transaction setting.

Use the connection method

connection.setconnectoption(

SQL.AUTOCOMMIT, SQL.AUTOCOMMIT_ON|OFF|DEFAULT)

to adjust the

connection's behavior to your needs after the connection has been established,

but before you have opened a database cursor.

With auto-commit turned on, transactions are effectively disabled. The

rollback() method will raise a NotSupportedError when used on such a

connection.