Question : Which of the following best describes a transaction in DBMS?
Solution :
Correct Answer : A set of logically related operations executed as a unit
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Question : Consider the operations: R(X), X = X – 500, W(X). If failure occurs after step 2, what ensures database correctness?
Solution :
Correct Answer : Rollback
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Question : Which state occurs after successful execution but before permanent storage of results?
Solution :
Correct Answer : Partially committed state
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Question : Which ACID property ensures that concurrent transactions do not interfere with each other?
Solution :
Correct Answer : Isolation
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Question : What is the correct sequence of basic transaction operations?
Solution :
Correct Answer : Read → Write → Commit
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Question : Which component is mainly responsible for ensuring Durability?
Solution :
Correct Answer : Recovery manager/log system
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Question : Which statement best describes Consistency in DBMS transactions?
Solution :
Correct Answer : Database must satisfy integrity constraints before and after execution
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Question : A transaction transfers ₹100 from Account A to B. After debit from A, system crashes before credit to B. Which property ensures recovery?
Solution :
Correct Answer : Atomicity
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Question : Which ACID property ensures that uncommitted changes are not visible to other transactions?
Solution :
Correct Answer : Isolation
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Question : Which of the following situations violates Atomicity in a DBMS transaction?
Solution :
Correct Answer : A transaction partially completes due to system failure
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Question : After a transaction is aborted, what are the possible next actions by the system?
Solution :
Correct Answer : Restart or kill the transaction
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Question : What is the primary purpose of the aborted state in a transaction?
Solution :
Correct Answer : To restore database consistency by undoing changes
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Question : Which of the following transitions is NOT possible in DBMS transaction states?
Solution :
Correct Answer : Failed → Committed
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Question : A transaction has completed all operations but changes are not yet permanently saved. In which state is it?
Solution :
Correct Answer : Partially Committed
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Question : Which of the following sequences correctly represents the normal lifecycle of a transaction in DBMS?
Solution :
Correct Answer : Active → Partially Committed → Committed → Terminated
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Question : Two schedules are view equivalent if they satisfy which condition?
Solution :
Correct Answer : Same initial reads, final writes, and update reads
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Question : Which of the following is NOT a type of serializability?
Solution :
Correct Answer : Strict serializability
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Question : In a precedence (serialization) graph, a schedule is conflict serializable iff:
Solution :
Correct Answer : Graph has no cycles
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Question : A schedule is said to be serializable if:
Solution :
Correct Answer : It produces the same result as some serial schedule
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Question : Which of the following conditions is necessary for conflict serializability?
Solution :
Correct Answer : Conflicting operations must preserve order
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