# Postgres Code Authoring

> Write or modify PostgreSQL queries, schemas, and migrations with parameter safety, data integrity, and operational verification. Use when a feature, bug fix, or refactor in a repository detected as PostgreSQL requires SQL, DDL, indexes, or migrations, even when the user does not name the database; do not use for review-only requests.

- Skill: `ch4570/postgres-code-authoring` (Agent Skill, multi-file: 5 files)
- Install (CLI): `npx skillmds@latest add ch4570/postgres-code-authoring`
- Raw SKILL.md: https://api.skillmd.com/api/skills/ch4570/postgres-code-authoring/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Data & Analytics
- Author: ch4570 (https://skillmd.com/u/ch4570)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/ch4570/postgres-code-authoring

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# PostgreSQL code authoring

Inspect the target PostgreSQL version, schema, migration tool, existing SQL, and access pattern before drafting. Preserve repository conventions; do not invent table, column, index, or constraint names.

## Construction contract

- Parameterize runtime values; never concatenate user or variable data into SQL text.
- Write the smallest result shape needed: explicit columns, deterministic ordering where order matters, and pagination suited to the access pattern. Use keyset pagination for deep traversal when the existing contract permits it.
- Model integrity in DDL with the appropriate primary key, `NOT NULL`, `UNIQUE`, `CHECK`, and foreign-key constraints. Match column types, defaults, and nullability to the actual domain contract.
- For a migration, prefer compatible staged changes. State lock/transaction constraints, data backfill plan, rollback path, and verification for destructive, large-table, type, or constraint changes.
- Propose indexes from an observed query predicate/join/order pattern and verify performance with `EXPLAIN` or `EXPLAIN (ANALYZE, BUFFERS)` where safe. Never claim a query is faster without evidence.
- Author only; do not execute data or schema changes without separate authorization.

Read [query construction](reference/kb/query-construction.md) for query work and [migration construction](reference/kb/migration-construction.md) for DDL or migrations. The installed `postgres-query-review`, `postgres-schema-design`, and `postgres-risk-check` dependencies provide the shared review rationale; use them as construction constraints, not as a request to write a review.

## Deliverable

Return the SQL or migration, stated assumptions, verification commands/tests, and rollback/operational notes when applicable.