Which of the following modes, when used with the LOCK TABLE statement, will cause the DB2
Database Manager to acquire a table-level lock that prevents other concurrent transactions from
accessing data stored in the table while the owning transaction is active?
A.
SHARE MODE
B.
ISOLATED MODE
C.
EXCLUSIVE MODE
D.
RESTRICT MODE
IN EXCLUSIVE MODE
Requests the acquisition of an exclusive lock for the application process. Until the lock is released, it prevents concurrent processes from executing any operations on the table.
Exception: Unless the lock is on a LOB table space, concurrent processes that are running at an isolation level of uncommitted read (UR) can execute read-only operations on the table.
Start of changeBe aware that an exclusive lock on a table space, table, or partition does not prevent other transactions from holding claims on the locked object.End of change
Notes
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Isolation levels
The isolation level that is associated with an application process determines the degree to which the data that is being accessed by that process is locked or isolated from other concurrently executing processes. The isolation level is in effect for the duration of a unit of work
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X lock (exclusive)
The lock owner can read or change the locked page or row. A concurrent process cannot acquire S, U, or X locks on the page or row. However, concurrent processes, such as those processes bound with the CURRENTDATA(NO) or ISOLATION(UR) bind options or running with YES specified for the EVALUNC subsystem parameter, can read the data without acquiring a page or row lock.
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