Consider a relational table \(r\) with sufficient number of records, having…
2011
Consider a relational table \(r\) with sufficient number of records, having attributes \(A_1, A_2, \dots ,A_n\) and let \(1 \leq p \leq n\). Two queries \(Q1\) and \(Q2\) are given below.
\(Q1: \pi_{A_1, \dots ,A_p} \left(\sigma_{A_p=c}\left(r\right)\right)\) where \(c\) is a constant
\(Q2: \pi_{A_1, \dots ,A_p} \left(\sigma_{c_1 \leq A_p \leq c_2}\left(r\right)\right)\) where \(c_1\) and \(c_2\) are constants.
The database can be configured to do ordered indexing on \(A_p\) or hashing on \(A_p\). 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\(Q1\)
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