Question 11068 – Set-Theory
January 9, 2024Constraints
January 9, 2024ER-Model
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Question 5
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In a schema with attributes A, B, C, D and E following set of functional dependencies are given
A → B A → C CD → E B → D E → A
Which of the following functional dependencies is NOT implied by the above set?
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CD → AC
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BD → CD
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BC → CD
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AC → BC
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Question 5 Explanation:
Apply membership test for all the functional dependencies.
Option (B):
BD → CD
BD+ = BD
i.e., BD cannot derive CD and hence is not implied.
Option (B):
BD → CD
BD+ = BD
i.e., BD cannot derive CD and hence is not implied.
Correct Answer: B
Question 5 Explanation:
Apply membership test for all the functional dependencies.
Option (B):
BD → CD
BD+ = BD
i.e., BD cannot derive CD and hence is not implied.
Option (B):
BD → CD
BD+ = BD
i.e., BD cannot derive CD and hence is not implied.