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.
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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