What are database transactions

Short answer

A transaction is a sequence of operations treated as a single unit of work. It must be Atomic, Consistent, Isolated, and Durable (ACID). For schema design context, see how to design a database schema from scratch. For migration safety, see how to implement database migrations.

Steps

1. Start a transaction: BEGIN;
2. Execute one or more SQL statements
3. Commit if all succeed: COMMIT;
4. Rollback on error: ROLLBACK;
5. Choose the appropriate isolation level for your use case

Tips

• Use the lowest isolation level that meets correctness requirements
• Keep transactions short to reduce locking contention
• For query optimization, see what are database indexes and how do they work