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X-Hacker.org- Advantage CA-Clipper Guide v5.5 - <b>record locking</b> http://www.X-Hacker.org [<<Previous Entry] [^^Up^^] [Next Entry>>] [Menu] [About The Guide]
   Record Locking
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   File locks and/or record locks must be acquired on data before it can
   be updated. Once data locks are acquired, they are maintained
   throughout the entire transaction to ensure that the updates can be
   made to the database during the commit of the transaction. Record and
   file locking is best performed before a transaction begins. If an
   update needs to be made to a record in order to complete the
   transaction, and the lock operation on that record is attempted during
   the transaction and is unsuccessful, the corresponding update cannot
   be performed. The application will most likely need to roll back the
   transaction. All previous update and insert operations performed prior
   to the failed data lock will be rolled back due to poor transaction
   programming. If all explicit data locks are acquired before a
   transaction begins, unnecessary rollbacks will be prevented.

   Explicit data locking during a transaction is not recommended, but
   is supported. Some data locking behavioral differences exist when
   data locks are performed during a transaction. Review the
   "Advantage TPS Special Conditions" section if data locking must be
   done during a transaction.


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