Database Design

Learn to THINK, not copy SQL patterns.

🎯 Selective Reading Rule

Read ONLY files relevant to the request! Check the content map, find what you need.

File Description When to Read

database-selection.md

PostgreSQL vs Neon vs Turso vs SQLite Choosing database

orm-selection.md

Drizzle vs Prisma vs Kysely Choosing ORM

schema-design.md

Normalization, PKs, relationships Designing schema

indexing.md

Index types, composite indexes Performance tuning

optimization.md

N+1, EXPLAIN ANALYZE Query optimization

migrations.md

Safe migrations, serverless DBs Schema changes

⚠️ Core Principle

• ASK user for database preferences when unclear

• Choose database/ORM based on CONTEXT

• Don't default to PostgreSQL for everything

Decision Checklist

Before designing schema:

• Asked user about database preference?

• Chosen database for THIS context?

• Considered deployment environment?

• Planned index strategy?

• Defined relationship types?

Anti-Patterns

❌ Default to PostgreSQL for simple apps (SQLite may suffice) ❌ Skip indexing ❌ Use SELECT * in production ❌ Store JSON when structured data is better ❌ Ignore N+1 queries