# Playbook: New Table

Use when: “新建表 / 加字段”

## Steps

1. Name with `snake_case` (`.ai/database.md` + `.ai/domain.md`)
2. Columns include `id, created_at, updated_at, deleted_at`
3. Write migration Up (+ Down)
4. Index FKs
5. Update `model` + repository
6. Never ship app code that queries columns not migrated
7. Document in PR
8. Review (Deployment + Docs items)