Correct Answer:
B. Durability
The ACID properties are fundamental principles in database management systems (DBMS) that guarantee reliable transaction processing. They ensure data integrity even in the event of errors, power failures, or other issues. Let's break down what each letter stands for:
- Atomicity: Ensures that a transaction is treated as a single, indivisible unit of operations. Either all operations within the transaction are completed successfully, or none of them are. There are no partial transactions.
- Consistency: Guarantees that a transaction brings the database from one valid state to another, maintaining all defined rules, constraints, and triggers.
- Isolation: Ensures that concurrent transactions do not interfere with each other. Each transaction appears to execute in isolation, as if it were the only transaction running.
- Durability: This is the correct answer. It guarantees that once a transaction has been committed, its changes are permanent and will survive any subsequent system failures, such as crashes or power outages. The committed data is stored persistently and will not be lost.
These properties collectively ensure the reliability and integrity of data in transactional systems.