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.
A. Idempotent
B. Changed
C. Repetitive
D. All of the above
Answer:A
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.
A. Idempotent B. Changed C. Repetitive D. All of the above