What is a transaction in a DBMS?

• A set of SQL commands

• A logical group of database operations

• A database schema

• A file stored in the database

Which ACID property ensures that a transaction's changes are permanent?

• Atomicity

• Consistency

• Isolation

• Durability

What does the 'A' in ACID stand for?

• Access

• Atomicity

• Association

• Action

When does a transaction enter the committed state?

• After a system failure

• After changes are permanently saved to the database

• During a read operation

• When the system is idle

Which recovery technique uses a log to restore a database after a system failure?

• Buffering and Caching

• Shadow Paging

• Log-based recovery

• Concurrency Control

In a system using immediate update, what happens if a rollback is initiated during a transaction?

• The database remains unchanged

• The log is destroyed and changes are discarded

• The old state of data is restored from the log

• The system terminates all active transactions

What does the isolation property of ACID ensure in a multi-transaction environment?

• Data integrity is maintained by reverting incomplete transactions

• No changes are visible until a transaction is committed

• Transactions can access and modify the same data simultaneously

• Transactions must be executed in the order they are submitted

Which of the following best describes a partially committed transaction?

• A transaction that has completed execution but not yet committed

• A transaction that failed during execution

• A transaction that is active and reading or writing data

• A transaction that has been aborted

How does concurrency control prevent conflicts in a database?

• By logging changes made during a transaction

• By using locking mechanisms to restrict access to data

• By buffering transactions for future execution

• By applying checkpoints at regular intervals

In a DBMS, what is the main function of the buffer manager?

• To manage concurrent access to the database

• To log all database transactions

• To store and transfer data between memory and disk

• To schedule and prioritize transactions