Database Transactions and Concurrency Control Quiz

1. Which of the following is NOT a potential problem in concurrent database access?

Lost updates

Dirty reads

Phantom reads

Committed transactions

2. Which approach prevents deadlocks by ordering resource requests consistently across all transactions?

Deadlock prevention

Deadlock avoidance

Deadlock detection

Deadlock recovery

3. Cascading rollback occurs when one transaction's rollback forces other transactions to roll back as well. True or False?

True

False

Submit

5. Which deadlock detection method repeatedly checks for cycles in the wait-for graph?

Prevention

Avoidance

Detection

Recovery

6. Multi-version concurrency control (MVCC) allows transactions to read different versions of the same data. True or False?

True

False

Submit

8. Which isolation level prevents both dirty reads and lost updates but allows phantom reads?

Read Uncommitted

Read Committed

Repeatable Read

Serializable

Submit

11. What does ACID stand for in database transactions?

Atomicity, Consistency, Isolation, Durability

Accuracy, Concurrency, Integration, Data

Application, Control, Index, Database

Access, Consistency, Instance, Deployment

Submit

13. Which concurrency control method uses timestamps to serialize transactions?

Two-phase locking

Timestamp ordering

Optimistic concurrency control

Multi-version concurrency control

14. A phantom read occurs when a transaction reads a set of rows twice and finds new rows that appeared between reads. True or False?

True

False

15. Which isolation level guarantees the highest level of data consistency?

Read Uncommitted

Read Committed

Repeatable Read

Serializable

Submit

17. What is a deadlock in database systems?

A transaction that never completes

Two or more transactions waiting indefinitely for resources held by each other

A permanent lock on a database table

An error that occurs during transaction rollback

18. Which locking mechanism allows multiple readers but only one writer?

Exclusive lock

Shared lock

Read-write lock

Deadlock

Submit

20. Which isolation level allows dirty reads but prevents lost updates?

Read Uncommitted

Read Committed

Repeatable Read

Serializable

General Databases Advanced Transactions and Concurrency Quiz

1. Which of the following is NOT a potential problem in concurrent database access?

2.

What first name or nickname would you like us to use?

2. Which approach prevents deadlocks by ordering resource requests consistently across all transactions?

3. Cascading rollback occurs when one transaction's rollback forces other transactions to roll back as well. True or False?

4. The ______ property in ACID ensures that only authorized users can access data.

5. Which deadlock detection method repeatedly checks for cycles in the wait-for graph?

6. Multi-version concurrency control (MVCC) allows transactions to read different versions of the same data. True or False?

7. A transaction's ______ property ensures that the database moves from one valid state to another.

8. Which isolation level prevents both dirty reads and lost updates but allows phantom reads?

9. Optimistic concurrency control assumes that conflicts between transactions are ______.

10. Two-phase locking (2PL) consists of a growing phase and a ______ phase.

11. What does ACID stand for in database transactions?

12. The ______ property ensures that committed transactions survive system failures.

13. Which concurrency control method uses timestamps to serialize transactions?

14. A phantom read occurs when a transaction reads a set of rows twice and finds new rows that appeared between reads. True or False?

15. Which isolation level guarantees the highest level of data consistency?

16. The ______ property ensures that a transaction either completes fully or not at all.

17. What is a deadlock in database systems?

18. Which locking mechanism allows multiple readers but only one writer?

19. A dirty read occurs when a transaction reads data that has been ______ but not yet committed.

20. Which isolation level allows dirty reads but prevents lost updates?