Database-Management-System
August 29, 2024Database-Management-System
August 29, 2024Database-Management-System
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Question 282
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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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lossless join 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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part dependency preserving and lossless join
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Question 282 Explanation:
The given decomposition is not lossless join because there is no common attributes between R1 and R2.
But the given decomposition is dependency preserving, A→ B is covered by R1 and C→ D is covered by R2.
But the given decomposition is dependency preserving, A→ B is covered by R1 and C→ D is covered by R2.
Correct Answer: B
Question 282 Explanation:
The given decomposition is not lossless join because there is no common attributes between R1 and R2.
But the given decomposition is dependency preserving, A→ B is covered by R1 and C→ D is covered by R2.
But the given decomposition is dependency preserving, A→ B is covered by R1 and C→ D is covered by R2.
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