Database locking
When multiple users attempt to simultaneously update a record, the database locking model ensures that the update from each user succeeds as a unit, but each update overwrites the previous update. An explicit (pessimistic) locking model prevents unexpected loss of data updates and controls the workflow when simultaneous updates from more than one user occur.
There are two locking models that can be used:
- Optimistic locking - A locking technique that allows simultaneous updates and detects conflicts in updates when the record is committed. By default Rational® ClearQuest® uses optimistic locking.
- Pessimistic locking - A locking technique that guarantees exclusive access to the record while it is being edited.