Slide 7.19: Committing changes

Committing Changes

By default, DML operations (INSERT, UPDATE, DELETE) are committed automatically as soon as they are executed. This is known as auto-commit mode. You can, however, disable auto-commit mode with the following method call on the Connection object:

   conn.setAutoCommit(false);

If you disable auto-commit mode, then you must manually commit or roll back changes with the appropriate method call on the Connection object:

   conn.commit( );

or:

   conn.rollback( );

A COMMIT or ROLLBACK operation affects all DML statements executed since the last COMMIT or ROLLBACK.

Note that:

If auto-commit mode is disabled and you close the connection without explicitly committing or rolling back your last changes, then an implicit COMMIT operation is executed.

Any DDL operation, such as CREATE or ALTER, always includes an implicit COMMIT. If auto-commit mode is disabled, this implicit COMMIT will not only commit the DDL statement, but also any pending DML operations that had not yet been explicitly committed or rolled back.