ACID

ACID properties ensure reliable database transactions through Atomicity, Consistency, Isolation, and Durability.

What is ACID?

ACID is a set of properties that guarantee database transactions are processed reliably: Atomicity (all or nothing), Consistency (valid state), Isolation (concurrent independence), Durability (permanent once committed).

ACID properties

Atomicity (complete or rollback), Consistency (data integrity), Isolation (concurrent transactions), Durability (survives failures).

Common misconceptions

"All databases are ACID" — Many NoSQL databases aren't
"ACID guarantees performance" — Tradeoffs with scalability
"ACID is always needed" — Depends on requirements