Database-Management-System
August 29, 2024Database-Management-System
August 29, 2024Database-Management-System
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Question 644
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A relation R = {A, B, C, D, E, F,G} is given with following set of functional dependencies:
F = {AD → E, BE → F, B → C, AF → G}
Which of the following is a candidate key ?
F = {AD → E, BE → F, B → C, AF → G}
Which of the following is a candidate key ?
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A
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AB
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ABC
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ABD
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Question 644 Explanation:
Since no functional dependency is having ABD in their right hand side, so every key should include ABD as a part of them to become a candidate key.
Now check whether ABD is itself a candidate key or not by finding the closure.
(ABD) + = { ABDCEFG }
since ABD can identify each attribute of the given relation uniquely.
So, ABD is the candidate key.
Now check whether ABD is itself a candidate key or not by finding the closure.
(ABD) + = { ABDCEFG }
since ABD can identify each attribute of the given relation uniquely.
So, ABD is the candidate key.
Correct Answer: D
Question 644 Explanation:
Since no functional dependency is having ABD in their right hand side, so every key should include ABD as a part of them to become a candidate key.
Now check whether ABD is itself a candidate key or not by finding the closure.
(ABD) + = { ABDCEFG }
since ABD can identify each attribute of the given relation uniquely.
So, ABD is the candidate key.
Now check whether ABD is itself a candidate key or not by finding the closure.
(ABD) + = { ABDCEFG }
since ABD can identify each attribute of the given relation uniquely.
So, ABD is the candidate key.