# Platform Database

> SQL database design, query optimization, and migration safety. Extends core-coding-standards with database-specific rules. Use when writing queries, schemas, or migrations.

- Skill: `majiayu000/platform-database` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add majiayu000/platform-database`
- Raw SKILL.md: https://api.skillmd.com/api/skills/majiayu000/platform-database/raw
- Safety review: pending (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Data & Analytics
- Author: majiayu000 (https://skillmd.com/u/majiayu000)
- Updated: 2026-09-21
- Page: https://skillmd.com/skills/majiayu000/platform-database

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# Principles

- Prefer UNION ALL over UNION unless you specifically need deduplication

# Rules

See `rules/` for detailed patterns.