Database ACID Transactions

A transaction is a single logical unit of database work. Transactions must satisfy ACID properties:

Atomicity**: All query steps succeed, or all fail (rollback).

Consistency**: Database schema rules are strictly enforced.

Isolation**: Concurrent transactions do not interfere with each other.

Durability**: Committed data survives system crashes.

SQL Transaction Example:

BEGIN;
UPDATE accounts SET balance = balance - 100 WHERE id = 1;
UPDATE accounts SET balance = balance + 100 WHERE id = 2;
COMMIT;