Generated & Identity Columns
GENERATED ALWAYS AS IDENTITY patterns. Practical PostgreSQL patterns for production queries.
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GENERATED ALWAYS AS IDENTITY patterns. Practical PostgreSQL patterns for production queries.
CREATE TABLE app.items (
id bigint GENERATED ALWAYS AS IDENTITY PRIMARY KEY,
line_total numeric(12,2) GENERATED ALWAYS AS (qty * unit_price) STORED
);When to reach for this: This pattern appears in application or reporting SQL you maintain.
INSERT INTO app.items (qty, unit_price) VALUES (2, 19.99);
SELECT line_total FROM app.items;What 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