Neco 2021 Computer Studies Question 21

Practice objective / multiple choice question 21 from the 2021 Neco Computer Studies examination.

Neco 2021 Computer Studies Objective / Multiple Choice Hard Difficulty
Question 21 NECO • 2021 • COMPUTER_STUDIES • objective

Given relation \(R(A,B,C,D,E)\) with functional dependencies \(A \rightarrow B\), \(BC \rightarrow D\), \(D \rightarrow E\), and \(AB \rightarrow C\), (a) list all candidate keys, (b) state the highest normal form of \(R\), and (c) decompose \(R\) into BCNF relations, indicating whether the decomposition is lossless‑join and dependency‑preserving.

Answer Options

A. Candidate key: {A}. Highest normal form: BCNF. BCNF decomposition: R1(A,B) and R2(B,C,D,E); not lossless‑join and dependency‑preserving.
Correct Answer B. Candidate key: {A}. Highest normal form: 1NF. BCNF decomposition: R1(B,C,D) and R2(A,B,C,E); lossless‑join but not dependency‑preserving.
C. Candidate key: {B,C}. Highest normal form: 3NF. BCNF decomposition: R1(A,B,C) and R2(C,D,E); lossless‑join but not dependency‑preserving.
D. Candidate key: {A,B}. Highest normal form: 2NF. BCNF decomposition: R1(A,B) and R2(B,C,D,E); lossless‑join and dependency‑preserving.
Correct Answer
B
Correct Option:
Candidate key: {A}. Highest normal form: 1NF. BCNF decomposition: R1(B,C,D) and R2(A,B,C,E); lossless‑join but not dependency‑preserving.

About This Question

This is Neco 2021 Computer Studies Question 21. It is one of the objective questions from the 2021 Neco Computer Studies examination.

Difficulty level: Hard .

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