Record Locking in QAB

Record locking gives the user exclusive access to the record at run-time. If a record is locked, no other user may update it until the user who locked it releases the lock. Record locking is one means of avoiding contention.

You can find out more about how record locking works in DP4 and its advantages and disadvantages here but we advise you to use record locking sparingly. You can find out about some alternatives methods of controlling contention here (this is a link to some C programming documentation, but you do not need to understand C to read it.)

In QAB a record is locked when it is read from the database and only unlocked when the rpogram next secures changes.

You can specify whether a locked record can be read from the database. For a report program, you can decide to produce the report even if a record is locked (and therefore not available for update) or to allow the operator to retry or abort the operation.

To lock a record:

In the table proessing dialog enable the Lock existing record option

To prevent locked records from being read:

In the table proessing dialog enable the Disallow locked record option

To present a Retry/Abort option if a record is locked:

1. In the table proessing dialog enable the Disallow locked record option In Main Table Processing answer yes to Disallow locked record ?
2. Create a map for the retry/abort question using the Message Assignment menu.