Once the lower-level lock is released, the operation cannot be undone by using the old values of updated data items, and must instead be undone by executing a compensating operation; such an operation is called

Related MCQs

• The situation where the lock waits only for a specified amount of time for another lock to be released is
• ____ ensures that once transaction changes are done, they cannot be undone or lost, even in the event of a system failure.
• An operation is said to be                      if executing it several times in a row gives the same result as executing it once.
• Which lock should be obtained to prevent a concurrent transaction from executing a conflicting read, insert or delete operation on the same key value.
• A(n) ____ lock exists when concurrent transactions are granted Read access on the basis of a common lock.
• In a ____ lock, the DBMS will lock an entire disk page.
• Assume transaction A holds a shared lock R. If transaction B also requests for a shared lock on R.
• There are “record-once” versions of the compact disk and digital video disk, which can be written only once; such disks are also called                      disks.
• Which of the syntax is correct for insert statement? i) insert into <table_name> values <list of values> ii) insert into <table_name> (column list) values <list of values>
• Instead of locking index leaf nodes in a two-phase manner, some index concurrency- control schemes use                        on individual key values, allowing other key values to be inserted or deleted from the same leaf.