Database-Management-System
August 29, 2024Database-Management-System
August 29, 2024Database-Management-System
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Question 329
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Consider a schema R = {A, B, C, D} and functional dependencies A → B and C → D.
Then the decomposition R1 = {A, B} and R2 = {C, D} is
Then the decomposition R1 = {A, B} and R2 = {C, D} is
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Dependency preserving but not lossless join
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Dependency preserving and lossless join
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Lossless join but not dependency preserving
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Neither lossless join nor dependency preserving
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Question 329 Explanation:
The given decomposition does not have any attribute in common, so not lossless decomposition.
The relation R1 covers FD A → B and relation R2 covers FD C → D.Hence the decomposition is functional dependency preserving.
The relation R1 covers FD A → B and relation R2 covers FD C → D.Hence the decomposition is functional dependency preserving.
Correct Answer: A
Question 329 Explanation:
The given decomposition does not have any attribute in common, so not lossless decomposition.
The relation R1 covers FD A → B and relation R2 covers FD C → D.Hence the decomposition is functional dependency preserving.
The relation R1 covers FD A → B and relation R2 covers FD C → D.Hence the decomposition is functional dependency preserving.
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