7.26 BEGIN/COMMIT/ROLLBACK syntax

By default, MySQL runs in autocommit mode. This means that as soon as you execute an update, MySQL will store the update on disk.

If you are using BDB tables, you can put MySQL into non-autocommit mode with the following command:

SET AUTOCOMMIT=0

After this you must use COMMIT to store your changes to disk or ROLLBACK if you want to ignore the changes you have made since the beginning of your transaction.

If you want to switch from AUTOCOMMIT mode for one serie of statements, you can use the BEGIN or BEGIN WORK statement.

BEGIN;
SELECT @A:=SUM(salary) FROM table1 WHERE type=1;
UPDATE table2 SET summmary=@A WHERE type=1;
COMMIT;

Note that if you are using non-transaction-safe tables, the changes will be stored at once, independent of the status of the autocommit mode.