Database Transactions and Concurrency Control Quiz

What is a transaction in a database?

• A type of database query

• A logical unit of work that must be completed or aborted

• A method of data retrieval

• A single SQL statement

Which property ensures that all operations of a transaction must be completed?

• Durability

• Atomicity

• Isolation

• Consistency

What does concurrency control aim to ensure?

• Serializability of transactions

• Data loss

• Increased transaction speed

• Data redundancy

Which of the following is NOT a locking method?

• Pessimistic locking

• Optimistic locking

• Exclusive locking

• Dynamic locking

What is the purpose of a transaction log?

• To keep track of all transactions that update the database

• To store user data

• To manage user permissions

• To enhance database performance

What happens during the isolation property of transactions?

• Transactions are executed in a serial manner

• Transactions are executed in parallel

• Data used during a transaction cannot be accessed by another transaction

• All transactions are aborted

Which method is used to prevent deadlocks?

• Two-phase locking

• Rollback

• Optimistic concurrency control

• Timestamping

What is the main disadvantage of using time stamping?

• It slows down transaction processing

• It is not reliable

• It is too complex to implement

• It requires additional memory

What does the term 'lost update' refer to?

• An update that is overwritten by another transaction

• A transaction that fails to execute

• Data that is deleted accidentally

• Data that is not saved

Which of the following is a characteristic of optimistic concurrency control?

• It is always faster than pessimistic methods

• It assumes that conflicts are rare

• It guarantees data integrity

• It requires locking