Transactions are composed of one or more OpenSQL statements. In general, a transaction begins with the first statement after connection to the database or the first statement following a commit or rollback. The precise starting point of a transaction depends on the DBMS to which you are connected. Subsequent statements are part of the transaction until a commit or rollback is executed. By default, an explicit commit or rollback must be issued to close a transaction.

To direct the DBMS to commit each database statement individually, use the SET AUTOCOMMIT ON statement. (This statement cannot be issued in an open transaction.) When autocommit is set on, a commit occurs automatically after every statement, except PREPARE and DESCRIBE.

If autocommit is on and a cursor is opened, the server or Enterprise Access product does not issue a commit until the CLOSE CURSOR statement is executed, because cursors are logically a single statement. A ROLLBACK statement can be issued when a cursor is open. To restore the default behavior (and enable multiquery transactions), issue the SET AUTOCOMMIT OFF statement.

To determine whether you are in a transaction, use the INQUIRE_SQL statement. For information about INQUIRE_SQL, see Status Information and Inquire_sql in the “OpenSQL Statements” chapter. To find out if autocommit is on or off, use dbmsinfo. For information about dbmsinfo, see The Dbmsinfo Function—Retrieve Information on Current Session.