Practice Library
All MCQs
Browse exam-wise, subject-wise, and country-wise MCQs with explanations.
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Correct Answer: A. one transaction overwrites another transaction’s update without proper control
Explanation:
The correct answer explains lost update problem in the context of Concurrency Control.
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Correct Answer: D. exclusive locks are held until the transaction commits or aborts
Explanation:
strict two-phase locking is used in Advanced DBMS because exclusive locks are held until the transaction commits or aborts.
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Correct Answer: D. the system checks for cycles in a wait-for graph and resolves them
Explanation:
This statement is correct because deadlock detection means that the system checks for cycles in a wait-for graph and resolves them.
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Correct Answer: D. rolls back effects of incomplete or aborted transactions
Explanation:
The correct answer explains undo operation in the context of Recovery.
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Correct Answer: A. one transaction overwrites another transaction’s update without proper control
Explanation:
lost update problem is used in Advanced DBMS because one transaction overwrites another transaction’s update without proper control.
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Correct Answer: C. exclusive locks are held until the transaction commits or aborts
Explanation:
This statement is correct because strict two-phase locking means that exclusive locks are held until the transaction commits or aborts.
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Correct Answer: D. transaction order is controlled using timestamps assigned to transactions
Explanation:
The correct answer explains timestamp ordering in the context of Concurrency Control.
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Correct Answer: A. rolls back effects of incomplete or aborted transactions
Explanation:
undo operation is used in Advanced DBMS because rolls back effects of incomplete or aborted transactions.
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Correct Answer: C. one transaction overwrites another transaction’s update without proper control
Explanation:
This statement is correct because lost update problem means that one transaction overwrites another transaction’s update without proper control.
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Correct Answer: D. a lock that allows concurrent reading but prevents conflicting writes
Explanation:
The correct answer explains shared lock in the context of Concurrency Control.
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Correct Answer: C. transaction order is controlled using timestamps assigned to transactions
Explanation:
timestamp ordering is used in Advanced DBMS because transaction order is controlled using timestamps assigned to transactions.
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Correct Answer: D. rolls back effects of incomplete or aborted transactions
Explanation:
This statement is correct because undo operation means that rolls back effects of incomplete or aborted transactions.
