database-patterns

<!-- directive-density: intentional (teaches migration anti-patterns; NEVER markers describe real production-break conditions, not aspirational guidance) --> # Database Patterns Comprehensive patterns for database migrations, schema design, and version management. Each category has individual rule files in `rules/` loaded on-demand. ## Quick Reference | Category | Rules | Impact | When to Use | |----------|-------|--------|-------------| | [Alembic Migrations](#alembic-migrations) | 2 | CRITICAL | Data migrations, branch management | | [Schema Design](#schema-design) | 3 | HIGH | Normalization, indexing strategies, NoSQL patterns | | [Versioning](#versioning) | 2 | HIGH | Changelogs, schema drift detection | | [Zero-Downtime Migration](#zero-downtime-migration) | 2 | CRITICAL | Expand-contract, pgroll, rollback monitoring | | [Database Selection](#database-selection) | 1 | HIGH | Choosing the right database, PostgreSQL vs MongoDB, cost analysis | **Total: 10 rules across 5 categories** This skill is a wrap around Alembic and PostgreSQL, not a replacement for their docs. Read `references/ork-delta.md` first: it holds the version floors, corrections and house conventions that upstream does not carry. Everything in the table below was removed on purpose. ## Upstream coverage (do not restate) These topics are vendor documentation. Fetch them from the source instead of re-teaching them here. | Topic | First-party source | |-------|--------------------| | Alembic autogene...