Normalization
August 29, 2024Database-Management-System
August 29, 2024Database-Management-System
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Question 316
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Consider a Relational schema R(A, B, C, D) and functional dependencies A → B and C → D.
Then the decomposition of R into R1 (A, B) and R2(C, D) is
Then the decomposition of R into R1 (A, B) and R2(C, D) is
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dependency preserving and lossless join
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lossless join but not dependency preserving
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dependency preserving but not lossless join
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neither dependency·preserving nor lossless join
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Question 316 Explanation:
R1(A,B) contains FD A→B
R2(C,D) contains FD C→D
So, yes dependency preserving.
But there is no common attribute between R1 and R2, hence not lossless join.
R2(C,D) contains FD C→D
So, yes dependency preserving.
But there is no common attribute between R1 and R2, hence not lossless join.
Correct Answer: C
Question 316 Explanation:
R1(A,B) contains FD A→B
R2(C,D) contains FD C→D
So, yes dependency preserving.
But there is no common attribute between R1 and R2, hence not lossless join.
R2(C,D) contains FD C→D
So, yes dependency preserving.
But there is no common attribute between R1 and R2, hence not lossless join.