Data / Knowledge library
Foreign Key
Constrains a column value to reference an existing key in another relation
Why learn Foreign Key?
It enforces referential integrity in the database
The problem it solves
It prevents orphaned or invalid cross-table relationships
Where it came from
Foreign Key is a database concept that constrains a column value to reference an existing key in another relation. Its guarantees and tradeoffs depend on the concrete implementation and operating context.
Build your understanding
Work through these exercises in order. Try the task before opening a reference.
- Define Foreign Key and distinguish it from a neighboring concept.
- Choose a realistic task where Foreign Key is appropriate.
- Identify a failure mode caused by misusing Foreign Key.
- Interpret a small design or result involving Foreign Key.
- Explain one tradeoff or limitation of Foreign Key.
Documentation and sources
- PostgreSQL Documentation (www.postgresql.org)