lock objects

[Former Member]

what are lock objects ?what is the purpose of lock objects ?

[amit_khare]

Check the link -

Regards,

Amit

Reward all helpful replies.

[Former Member]

Lock mode

Defines how to synchronize table record access by several users

Exclusive lock or read lock

The locked data can be read or processed by one user only. A request for another exclusive lock or for a shared lock is rejected.

Shared lock or write 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. Requests for further shared locks are accepted, even if they are issued by different users, but exclusive locks are rejected.

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

[Former Member]

<b>purpose:</b> If multiple user try to access a database object, inconsistency may occer. To avoid that inconsistency and to let multiple user give the accessibility of the database objects the locking mechanism is used.

<b>

Steps:</b> first we create a loc object in se11 . Suppose for a table mara. It will create two functional module.:

1. enque_lockobject

1. deque_lockobject

before updating any table first we lock the table by calling enque_lockobject fm and then after updating we release the lock by deque_lockobject.