Constraints, keys, and integrity

Constraints are guarantees the database keeps even when a buggy deploy does not. Foreign keys, uniqueness, and checks belong in the schema.

Lesson 2.23m 53sIntermediate9.4k students

Chapters

3:53

0:00Introduction
0:21Example of Foreign Keys in a database
0:32What is a Primary key?
1:19What is a foreign key?
2:02What do foreign keys do?
3:27Review of Foreign Keys

Lesson contentNotes

What this lesson covers

Enforce relationships with foreign keys
Use unique and check constraints as invariants
Choose delete behaviour deliberately

This lesson sits in Schema Design, part of PostgreSQL for Developers. It assumes what came before it and leads directly into the next lesson in the module.

In this lesson you will

Enforce relationships with foreign keys
Use unique and check constraints as invariants
Choose delete behaviour deliberately

Resources

PostgreSQL documentation (opens in a new tab)

The official reference for the tools used in this lesson.

Link