Explanation: Logging of old-value and new-value information is called physical logging. 5. To perform logical redo or undo, the database state on disk must be operation _____________, that is, it should not have partial effects of any operation.
A. Persistent
B. Resistant
C. Consistent
D. None of the mentioned
Answer:A
Explanation: Logging of old-value and new-value information is called physical logging. 5. To perform logical redo or undo, the database state on disk must be operation _____________, that is, it should not have partial effects of any operation.
A. Persistent B. Resistant C. Consistent D. None of the mentioned
Explanation: Data structures such as B+-trees would not be in a consistent state, and neither logical redo nor logical undo operations can be performed on an inconsistent data structure. 6. An operation is said to be __________ if executing it several times in a row gives the same result as executing it once.