Why this chapter matters
Business workflows such as checkout or inventory updates require all-or-nothing correctness.
What you will learn
- Explain ACID guarantees in practical PostgreSQL terms.
- Use BEGIN, COMMIT, and ROLLBACK for safe multi-step operations.
- Recognize isolation concerns in concurrent transaction scenarios.
Lessons in this chapter
- Transaction lifecycleControl units of work explicitly with BEGIN, COMMIT, and ROLLBACK. Read the full guide →
- Atomic workflow designGroup dependent SQL statements so partial updates cannot be committed.
- Isolation and concurrencyUnderstand how concurrent transactions can interact and why isolation levels matter.
- Failure handling patternsUse transactional guards and retries safely in application-facing SQL paths.
Study task
Implement a PostgreSQL transaction that inserts an order, decrements inventory, and rolls back if stock is insufficient.
Chapter checkpoint
What should happen in PostgreSQL if one step in a transaction fails and you issue ROLLBACK?
All changes made in that transaction are undone, returning data to its prior consistent state.