Transaction (SAP Library - Reference Manual 7.2 (BC))

Transaction

A transaction is a sequence of database operations that form a unit with regard to data backup and synchronization.

Transactions are closed with COMMIT or ROLLBACK:

COMMIT: all modifications made to the serverdb within the transaction are kept.

ROLLBACK: all of the modifications to the serverdb made by the transaction are reversed, even those that were terminated with the SUBTRANS END statement ( subtransactions).

Modifications terminated with COMMIT cannot be reversed with ROLLBACK.

COMMIT and ROLLBACK implicitly open a new transaction.

Locks

The database system draws a distinction between SHARE locks and exclusive locks:

SHARE locks prevent locked tables or table rows from being modified by other users while still allowing read access.

Exclusive locks prevent other users from both reading and modifying the locked objects, while the user who specified the lock can modify these objects.

Tables and table rows are locked in a transaction with a lock mode that is determined when the user logs onto the database system ( CONNECT statement) or can be set with the LOCK option.

See also:

Transactions

COMMIT statement

ROLLBACK statement