Primary & Foreign Keys
Referential integrity and ON DELETE actions. Practical PostgreSQL patterns for production queries.
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Referential integrity and ON DELETE actions. Practical PostgreSQL patterns for production queries.
CREATE TABLE app.orders (
id bigint GENERATED ALWAYS AS IDENTITY PRIMARY KEY,
account_id bigint NOT NULL REFERENCES app.accounts(id) ON DELETE RESTRICT
);When to reach for this: This pattern appears in application or reporting SQL you maintain.
DELETE FROM app.accounts WHERE id = 1; -- fails if orders exist with RESTRICTWhat this demonstrates:
| Alternative | Use When | Don't Use When |
|---|---|---|
| ORM query builder | Team standardizes on one stack | Complex SQL becomes opaque |
| Materialized view | Repeat expensive aggregates | Needs refresh strategy |
| Warehouse replica | Heavy BI scans | Not for OLTP latency |
Use multiline template strings or SQL files; lint in CI.
When you need unique rows without aggregates.
Sort can use index order if query matches index columns.
Stack versions: This page was written for PostgreSQL 18.4 (stable 18, maintenance 17), pgvector 0.8+, PgBouncer 1.x, Patroni 3.x, and PostGIS 3.5+.
Reviewed by Chris St. John·Last updated Jul 18, 2026