Question 2636 – KVS 30-12-2018 Part-A
April 15, 2024Computer-Networks
April 15, 2024Transactions
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Question 49
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The following table has two attributes X and Y where X is the primary key and Y is the foreign key referencing X with on delete cascade
The set of all tuples that must be additionally deleted to preserve referential integrity when the tuple (3,4) is deleted is:
The set of all tuples that must be additionally deleted to preserve referential integrity when the tuple (3,4) is deleted is:
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(4,3) and (6,4)
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(2,4) and (7,2)
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(3,2) and (9,5)
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(3,4),(4,3) and (6,4)
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Question 49 Explanation:
→ On removal of row (3,4), row (4,3) must also be deleted as they depend on value 3.
→ On removal of row (4,3), row (2,4) and (6,4) must also be deleted as it depends on value 4.
→ As there is no option with row(2,4) and also the question says additional tuples should be deleted. So, option D is eliminated.
→ On removal of row (4,3), row (2,4) and (6,4) must also be deleted as it depends on value 4.
→ As there is no option with row(2,4) and also the question says additional tuples should be deleted. So, option D is eliminated.
Correct Answer: A
Question 49 Explanation:
→ On removal of row (3,4), row (4,3) must also be deleted as they depend on value 3.
→ On removal of row (4,3), row (2,4) and (6,4) must also be deleted as it depends on value 4.
→ As there is no option with row(2,4) and also the question says additional tuples should be deleted. So, option D is eliminated.
→ On removal of row (4,3), row (2,4) and (6,4) must also be deleted as it depends on value 4.
→ As there is no option with row(2,4) and also the question says additional tuples should be deleted. So, option D is eliminated.
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