Lock objects are function modules to avoid accessing data by two or more users.
There are two types of lock objects are available, DEQUEE, ENQUEE.
Type of locks:
Exclusive Lock: The locked data can be read or processed by one user only.
Shared Lock: Several users can read the same data at the same time, but as soon as a user edits the data, a second user can no longer access this data.
Exclusive but not cumulative lock: Exclusive locks can be requested by the same transaction more than once and handled successively, but an exclusive but not cumulative lock can only be requested once by a given transaction. All other lock requests are rejected.