36 SAP ABAP Q UESTIONS AND A NSWERS 5. Fill the lock parameter. 6. Save, check, and activate the lock objects. 54. What is lock mode? Lock mode is a synchronization method of accessing records by several users at the same time. There are three types of lock modes: Exclusive lock Shared or read lock Exclusive but not cumulative 55. Explain the different lock modes. Exclusive lock --Exclusive or write lock mode does not allow other users to change or modify the data while it is locked by one user. Only one user at a time can read or process the locked data. Further requests for an exclusive lock or shared lock are not accepted. Shared or read lock --In this mode, more than one user can read the same data at the same time. When the user changes the data, then another user can no longer access this data. Other users cannot set an exclusive lock when a shared lock is in effect. Exclusive but not cumulative lock --An exclusive but not cumulative lock can be allowed only once in the same transaction. It cannot be allowed more than once like an exclusive lock on the same transaction. Requests for this lock cannot be accepted if the exclusive lock is already set on the transaction. 56. How are match codes defined? Match codes are defined on two levels: Match code object --The match code object is used to depict the broad logical view of various tables. It does not exist physically. To make the match code object, first an area of