What are the ACID properties of a transaction?

ACID stands for Atomicity, Consistency, Isolation, and Durability.

Atomicity means the transaction's work succeeds as a unit or is rolled back. Consistency means committed transactions should move the database from one valid state to another while respecting defined integrity rules. Isolation controls how concurrent transactions interact and what intermediate effects they can observe. Durability means that once a transaction is successfully committed, its committed changes survive subsequent failures according to SQL Server's durability guarantees.

ACID properties are fundamental to reliable transactional database systems.