Database-Management-System
August 29, 2024Database-Management-System
August 29, 2024Database-Management-System
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Question 361
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Consider a 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
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Dependency preserving and lossless Join
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Lossless Joint but not dependency preserving
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Dependency preserving but not lossless Join
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Not dependency preserving and not lossless Join
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Question 361 Explanation:
There is no common attribute in the R1 and R2. So the given decomposition is not lossless join.
But they are dependency preserving because A → B is covered by R1 and C → D is covered by R2.
But they are dependency preserving because A → B is covered by R1 and C → D is covered by R2.
Correct Answer: C
Question 361 Explanation:
There is no common attribute in the R1 and R2. So the given decomposition is not lossless join.
But they are dependency preserving because A → B is covered by R1 and C → D is covered by R2.
But they are dependency preserving because A → B is covered by R1 and C → D is covered by R2.