LESSON 2.2
Constraints, keys, and integrity
Learn key techniques and workflows in PostgreSQL for Developers.
3m
intermediate
9,433 students
Overview
Constraints are guarantees the database keeps even when a buggy deploy does not. Foreign keys, uniqueness, and checks belong in the schema.
In this lesson you will:
- Enforce relationships with foreign keys
- Use unique and check constraints as invariants
- Choose delete behaviour deliberately
Pro Tip
Use caching and revalidation wisely to ensure your app stays fast and data remains fresh without unnecessary requests.