Link Inner Join - Locking (Magic xpa 4.x)

In Physical transactions only, when Magic xpa needs to lock a record, Magic xpa generates a lock in the underlying RDBMS.

In SQL gateways that use logical locking, the logical locking is done simultaneously for the main and the joined tables when Access/Share modes on the Main Source are Write/Write.

In SQL gateways that use physical locking, the SQL gateway checks whether the RDBMS allows a FOR UPDATE clause for a joined table Select:

If the RDBMS, such as Oracle allows a FOR UPDATE clause for a joined table Select, the Lock is done simultaneously for those main and joined tables that are in Write Access mode.

If the RDBMS, such as DB2, does not allow a FOR UPDATE clause for a joined table SELECT, the lock is done separately for each table.

If a join table was opened in the task with read access, Magic xpa will try to lock only the Main Source and not the joined table.

When Magic xpa needs to update the database, it updates each joined table separately according to the position key for that table.