name: postgresql-table-design description: Use this skill when designing or reviewing a PostgreSQL-specific schema. Covers best-practices, data types, indexing, constraints, performance patterns, and advanced features
PostgreSQL Table Design
When to Use
- Designing a new PostgreSQL schema, or reviewing one before it ships.
- Choosing column types, keys, constraints, or indexes for PostgreSQL specifically.
- Deciding whether and how to partition a large table, or how to store semi-structured data.
- Planning a schema change on a live database without downtime.
The rules and decision points for a PostgreSQL schema. The full data-type catalog, workload
patterns (update-heavy, insert-heavy, upsert, schema evolution), extensions, JSONB indexing,
and worked DDL examples are in references/details.md; open it when a section below points there.
Core Rules
- Define a PRIMARY KEY for reference tables (users, orders, etc.). Not always needed for time-series/event/log data. When used, prefer
BIGINT GENERATED ALWAYS AS IDENTITY; useUUIDonly when global uniqueness/opacity is needed. - Normalize first (to 3NF) to eliminate data redundancy and update anomalies; denormalize only for measured, high-ROI reads where join performance is proven problematic.
- Add NOT NULL everywhere it is semantically required; use DEFAULTs for common values.