The DBI defines a method called
commit() for explicitly committing any uncommitted
data within the current transaction. This method is executed against
a valid database handle:
$dbh->commit();
If commit() is invoked while
AutoCommit is enabled, a warning will be displayed
similar to:
commit ineffective with AutoCommit
which merely tells you that the database changes have already been
committed. This warning will also be displayed when
commit() is invoked against a database that has no
transaction support because, by definition,
AutoCommit will be enabled.