Free Test Transactions and Concu... – Databas...

Q1: What is a transaction in a database?

A. A sequence of operations performed as a single logical unit B. A single SQL query C. A database backup D. A database index

Q2: Which property of transactions ensures that all operations are completed successfully or none at all?

A. Atomicity B. Consistency C. Isolation D. Durability

Q3: What does the Consistency property ensure?

A. Database remains in a valid state before and after transaction B. Transactions are executed sequentially C. Changes are permanent after commit D. Transactions cannot interfere with each other

Q4: Which transaction property ensures that transactions are executed independently?

A. Isolation B. Durability C. Atomicity D. Consistency

Q5: What does Durability mean in transactions?

A. Once committed, changes persist even after system failure B. All operations must complete successfully C. Transactions cannot be seen by others D. Data must be consistent

Q6: Which SQL command commits a transaction?

A. COMMIT B. ROLLBACK C. SAVEPOINT D. BEGIN TRANSACTION

Q7: Which command undoes changes in a transaction?

A. ROLLBACK B. COMMIT C. SAVEPOINT D. BEGIN

Q8: What is a savepoint in SQL?

A. A point within a transaction to which you can rollback B. A type of index C. A locking mechanism D. A transaction isolation level

Q9: Which isolation level prevents dirty reads?

A. READ COMMITTED B. READ UNCOMMITTED C. REPEATABLE READ D. SERIALIZABLE

Q10: Which isolation level provides the highest level of isolation?

A. SERIALIZABLE B. READ COMMITTED C. READ UNCOMMITTED D. REPEATABLE READ

Q11: What is a dirty read?

A. Reading uncommitted data from another transaction B. Reading committed data twice C. Reading data that does not exist D. Reading data after commit

Q12: What problem does phantom read refer to?

A. New rows appear in result set in repeated queries within the same transaction B. Reading uncommitted data C. Data overwritten by concurrent transactions D. Lost updates

Q13: Which of the following is a concurrency control technique?

A. Locking B. Indexing C. Normalization D. Partitioning

Q14: What is the purpose of a deadlock?

A. A situation where two or more transactions wait indefinitely for each other’s locks B. A mechanism to speed up transactions C. A transaction isolation level D. A recovery technique

Q15: How can deadlocks be resolved?

A. Timeouts or deadlock detection and rollback B. Increasing isolation level C. Adding indexes D. Using views

Q16: What is a lost update problem?

A. Two transactions overwrite each other’s changes B. A transaction fails to commit C. Data becomes inconsistent D. A transaction reads uncommitted data

Q17: Which SQL statement starts a transaction?

A. BEGIN TRANSACTION B. START C. CREATE TRANSACTION D. OPEN TRANSACTION

Q18: What happens if a transaction is not committed or rolled back?

A. Changes remain uncommitted and can cause locks or inconsistencies B. Changes are saved automatically C. Transaction ends successfully D. Database crashes

Q19: What is optimistic concurrency control?

A. Allowing transactions to execute without locking and validating before commit B. Locking data before access C. Using indexes to speed queries D. Rolling back changes automatically

Quiz for Transactions and Concurrency Control in SQL