Gce Model Questions Vol1 2020 Computer Studies Question 26

Practice objective / multiple choice question 26 from the 2020 Gce Model Questions Vol1 Computer Studies examination.

Gce Model Questions Vol1 2020 Computer Studies Objective / Multiple Choice Hard Difficulty
Question 26 GCE_MODEL_QUESTIONS_VOL1 • 2020 • COMPUTER_STUDIES • objective

For a relation R(A,B,C,D,E) the following functional dependencies hold: (A \rightarrow B), (A \rightarrow C), (BC \rightarrow D), (D \rightarrow E). (a) List all candidate keys of R. (b) The relation is decomposed into R1(A,B,C), R2(B,D) and R3(D,E). State whether this decomposition is lossless‑join and whether it preserves all functional dependencies.

Answer Options

A. Candidate key: {A, B}. Decomposition is lossless‑join and dependency‑preserving.
Correct Answer B. Candidate key: {A}. Decomposition is lossless‑join but not dependency‑preserving.
C. Candidate key: {B, C}. Decomposition is not lossless‑join and not dependency‑preserving.
D. Candidate key: {A}. Decomposition is not lossless‑join but dependency‑preserving.
Correct Answer
B
Correct Option:
Candidate key: {A}. Decomposition is lossless‑join but not dependency‑preserving.

About This Question

This is Gce Model Questions Vol1 2020 Computer Studies Question 26. It is one of the objective questions from the 2020 Gce Model Questions Vol1 Computer Studies examination.

Difficulty level: Hard .

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