Transaction Management

Q1. ACID properties of a transaction stand for:

1. A.Atomicity, Concurrency, Isolation, Durability
2. B.Addition, Consistency, Integrity, Durability
3. C.Atomicity, Consistency, Isolation, Durability✓ Correct
4. D.Atomicity, Consistency, Isolation, Dependency

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Q2. Atomicity means that a transaction:

1. A.Runs in isolation from all other transactions
2. B.Is either fully completed or fully rolled back✓ Correct
3. C.Is stored permanently on the disk after start
4. D.Can be partially completed and then paused

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Q3. Consistency ensures that a transaction:

1. A.Never fails regardless of the operations within
2. B.Is stored permanently on disk after the commit
3. C.Runs concurrently with other active transactions
4. D.Brings the database from one valid state to another✓ Correct

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Q4. Isolation ensures that:

1. A.Transactions are never allowed to execute concurrently
2. B.All transactions see each other's changes immediately
3. C.Only one transaction can exist in the system at a time
4. D.Concurrent transactions do not interfere with each other✓ Correct

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Q5. Durability ensures that:

1. A.Data is stored only in volatile memory and not on stable disk
2. B.Changes can be undone at any time even after transaction commit
3. C.Committed transaction changes persist even after system failure✓ Correct
4. D.Transactions are temporary and their changes are never saved

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Q6. The COMMIT operation in a transaction:

1. A.Pauses the active transaction
2. B.Makes all changes permanent✓ Correct
3. C.Undoes all current changes
4. D.Starts a new transaction

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Q7. The ROLLBACK operation in a transaction:

1. A.Undoes all changes made by the transaction✓ Correct
2. B.Starts a new transaction in the session
3. C.Deletes the database and all stored data
4. D.Saves all changes and makes them permanent

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Q8. A transaction that has not yet been committed or rolled back is called:

1. A.Committed
2. B.Active✓ Correct
3. C.Aborted
4. D.Terminated

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Q9. Which of the following is a transaction state?

1. A.All of these: Active, Partially committed, Committed, Failed, Aborted✓ Correct
2. B.Only Aborted is considered a valid state for a transaction process
3. C.Only Active is considered a valid state for a transaction in a DBMS
4. D.Only Committed is considered a valid state for a transaction to be

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Q10. A schedule in transaction management is:

1. A.A single SQL query executed against the database tables
2. B.A backup plan for recovering from a system level failure
3. C.A type of index structure for speeding up data lookups
4. D.A sequence of operations from one or more transactions✓ Correct

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Q11. A serial schedule is one where:

1. A.Only one transaction is allowed in the database system total
2. B.Operations are randomly ordered across multiple transactions
3. C.Transactions execute one after another without interleaving✓ Correct
4. D.Transactions execute concurrently with operations interleaved

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Q12. A serializable schedule is:

1. A.A schedule whose result is equivalent to some serial schedule✓ Correct
2. B.A schedule where all transactions run simultaneously at once
3. C.A schedule that is always a serial schedule by definition
4. D.A schedule with no transactions present within its timeline

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Q13. Conflict serializability is tested using:

1. A.Hash table (bucket-based structure)
2. B.B-tree index (balanced tree structure)
3. C.ER diagram (entity relationship model)
4. D.Precedence graph (serialization graph)✓ Correct

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Q14. Two operations conflict if:

1. A.They belong to different transactions, access the same data item, and at least one is a write✓ Correct
2. B.They are both read operations accessing the same data item from within different transactions
3. C.They belong to the same transaction and access different data items within the transaction
4. D.They access different data items from different transactions without any write operations

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Q15. A dirty read occurs when:

1. A.No read operation occurs between any concurrent transactions
2. B.A transaction reads data that it has written by itself before
3. C.A transaction reads data written by an uncommitted transaction✓ Correct
4. D.A transaction reads data that has already been fully committed

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Q16. A non-repeatable read occurs when:

1. A.No read operation is performed during the entire transaction
2. B.All reads from a transaction return the same consistent value
3. C.A transaction reads a value once and never accesses it again
4. D.A transaction reads the same item twice and gets different values✓ Correct

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Q17. A phantom read occurs when:

1. A.A transaction re-executes a query and finds new rows added by another transaction✓ Correct
2. B.A transaction reads no rows at all from the table during its entire execution
3. C.A transaction creates a table and populates it with data from another data source
4. D.A transaction deletes rows from the table and those changes are then committed

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Q18. The READ UNCOMMITTED isolation level allows:

1. A.No anomalies of any kind during transaction processing
2. B.Dirty reads, non-repeatable reads, and phantom reads✓ Correct
3. C.Only phantom reads but prevents all other read anomalies
4. D.Only non-repeatable reads but prevents all dirty reads

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Q19. The SERIALIZABLE isolation level provides:

1. A.Complete isolation from other transactions✓ Correct
2. B.Only dirty read prevention mechanism
3. C.Faster performance than other levels
4. D.No isolation between any transactions

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Q20. A cascading rollback occurs when:

1. A.No rollback is needed because every transaction completes without any failures
2. B.Only one transaction rolls back while all other transactions continue normally
3. C.One transaction's rollback forces other dependent transactions to also roll back✓ Correct
4. D.All transactions commit successfully without any errors during their execution

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Q21. View serializability is:

1. A.Not related to serializability in any way
2. B.Less restrictive than conflict serializability✓ Correct
3. C.The same as conflict serializability criteria
4. D.More restrictive than conflict serializability

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Q22. A recoverable schedule ensures that:

1. A.A transaction commits only after all transactions whose data it read have committed✓ Correct
2. B.All transactions must run serially with no concurrent execution allowed at all
3. C.Transactions can commit in any order regardless of their data reading dependencies
4. D.Rollbacks are never needed because all transactions always complete successfully

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Q23. A cascadeless schedule is one where:

1. A.All transactions must abort immediately
2. B.Transactions only read committed data✓ Correct
3. C.Transactions can read uncommitted data
4. D.No reads are allowed in any transaction

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Q24. A strict schedule requires that:

1. A.No transaction reads or writes data written by an uncommitted transaction✓ Correct
2. B.Transactions can freely read uncommitted data from other transactions
3. C.Commits are not required for transactions to be considered complete
4. D.Only serial schedules are allowed for all transactions in the system

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Q25. The precedence graph for testing conflict serializability has:

1. A.Nodes for SQL statements and edges for their execution ordering
2. B.Nodes for transactions and edges for conflicting operation pairs✓ Correct
3. C.Nodes for data items and edges for transactions accessing them
4. D.No nodes or edges are used in this graph representation at all

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Q26. Testing view serializability is:

1. A.NP-complete✓ Correct
2. B.Linear time
3. C.Logarithmic time
4. D.Constant time

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Q27. The READ COMMITTED isolation level prevents:

1. A.No anomalies of any kind
2. B.All anomalies including phantoms
3. C.Only dirty reads alone✓ Correct
4. D.Dirty and non-repeatable reads

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Q28. The REPEATABLE READ isolation level prevents:

1. A.All anomalies including phantom reads
2. B.Dirty reads and non-repeatable reads✓ Correct
3. C.Only dirty reads from transactions
4. D.No anomalies of any kind at all

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Q29. In a multi-version concurrency control (MVCC) system:

1. A.Transactions must be serial with no concurrent execution allowed at all
2. B.Multiple versions of data items are maintained for concurrent access✓ Correct
3. C.Only one version of each data item exists at any given point in time
4. D.Locks are always required for every read and write operation performed

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Q30. A blind write is:

1. A.A committed transaction that has been successfully applied
2. B.A query optimization technique that reduces disk access
3. C.A read operation that is not followed by any write at all
4. D.A write operation without reading the current value first✓ Correct

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