Question

Which of the following file organizations is/are I/O efficient for the scan operation in DBMS?}

• A. Sorted
• B. Heap
• C. Unclustered tree index
• D. Unclustered hash index

Hint:

Heap and sorted file organizations are efficient for scans due to their sequential access patterns, reducing random I/O.

Answer 1

The Correct Option is A

In a scan operation, sequential access to data minimizes disk I/O. Sorted file organizations provide sequential access and are efficient for scan operations. Thus, Option (A) is correct.
Heap files store data without any particular order, but for a full scan, every block is accessed sequentially. This makes heap files I/O efficient for scan operations. Hence, Option (B) is correct.
Unclustered tree indexes, however, are not I/O efficient for scans because data blocks may not be accessed sequentially, leading to multiple random I/O operations. Hence, Option (C) is incorrect.
Unclustered hash indexes are designed for equality searches and not optimized for scan operations. Random I/O makes them inefficient for scans. Thus, Option (D) is incorrect. Final Answer: \[ \boxed{\text{(A), (B)}} \]