Consider a relational table r with sufficient number of records, having attributes A1, A2,…, An and let 1 <= p <= n.

Question

The database can be configured to do ordered indexing on Ap or hashing on Ap. Which of the following statements is TRUE?
(A) Ordered indexing will always outperform hashing for both queries
(B) Hashing will always outperform ordered indexing for both queries
(C) Hashing will outperform ordered indexing on Q1, but not on Q2
(D) Hashing will outperform ordered indexing on Q2, but not on Q1.
 

Answer 1

$A_p = C$ -Hashing would mean constant time to get the tuple from the index.

$C_1 \leq A_p \leq C_2$- We need to scan a range of values in index to determined the matching tuples.

So, C should be the answer.

Comments

Sir can u plz explain why hashing can't be performed in option D ?