For simplified programming of OLTP applications, ADABAS provides optimistic locks. They make it possible to write an application for operation in isolation level 0 without the usual repetitive check reading being necessary.
For this purpose, an optimistic lock is demanded when accessing a database object. When updating the same database object, the application program receives a message if, in the meantime, other users have made modifications to this database object. Otherwise, the update is executed without the application having to verify the database object with a check reading.
Optimistic locks do not preclude share locks or exclusive locks.