UGC-NET | UGC NET CS 2017 Jan – II | Question 19

Consider a schema R(MNPQ) and functional dependencies M → N, P → Q. Then the decomposition of R into R₁ (MN) and R₂(PQ) is________.
(A) Dependency preserving but not lossless join
(B) Dependency preserving and lossless join
(C) Lossless join but not dependency preserving
(D) Neither dependency preserving nor lossless join.


Answer: (A)

Explanation: Schema R(MNPQ) is decomposed into R₁(MN) M → N is preserved and R₂(PQ) P → Q is also preserved, dependency will be preserved and there will be no loss of any dependency.
So, option (A) is correct.


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