TRANSBEGIN

Discussion

This command allows you to designate the beginning of a logical logging transaction from the QUERY subsystem in a similar manner to the IMAGE DBBEGIN intrinsic.

A transaction is defined as a sequence of one or more modifications which changes a data base from one consistent state to another. Logging allows you to keep a record of transactions in the event of a system failure. Marking the transaction with a TRANSBEGIN and TRANSEND, allows you to restore your data base to a consistent state by suppressing those transactions that failed to complete. For further information on transaction logging, refer to the IMAGE Reference Manual.

Logging must have already been enabled from the IMAGE subsystem for the TRANSBEGIN command to work. Consult your data base administrator about enabling the logging facility. If logging has not been enabled, you will receive the following message:

   LOGGING NOT ENABLED FOR THIS USER

If you enter the TRANSBEGIN command twice without entering an intervening TRANSEND command, the following message is printed:

      A TRANSACTION IS IN PROGRESS

      TRANSEND MUST BE CALLED BEFORE ANOTHER TRANSBEGIN

Entering EXIT while transaction logging is in effect will not abort the logging process. Note, however, that when logging completes, QUERY performs an implicit TRANSEND, your data base is closed, and the subsystem is exited.