Database Design

1---
2name: database-design
3description: Database design principles and decision-making. Schema design, indexing strategy, ORM selection, serverless databases.
4allowed-tools: Read, Write, Edit, Glob, Grep
5---
6 
7# Database Design
8 
9> **Learn to THINK, not copy SQL patterns.**
10 
11## 🎯 Selective Reading Rule
12 
13**Read ONLY files relevant to the request!** Check the content map, find what you need.
14 
15| File | Description | When to Read |
16|------|-------------|--------------|
17| `database-selection.md` | PostgreSQL vs Neon vs Turso vs SQLite | Choosing database |
18| `orm-selection.md` | Drizzle vs Prisma vs Kysely | Choosing ORM |
19| `schema-design.md` | Normalization, PKs, relationships | Designing schema |
20| `indexing.md` | Index types, composite indexes | Performance tuning |
21| `optimization.md` | N+1, EXPLAIN ANALYZE | Query optimization |
22| `migrations.md` | Safe migrations, serverless DBs | Schema changes |
23 
24---
25 
26## ⚠️ Core Principle
27 
28- ASK user for database preferences when unclear
29- Choose database/ORM based on CONTEXT
30- Don't default to PostgreSQL for everything
31 
32---
33 
34## Decision Checklist
35 
36Before designing schema:
37 
38- [ ] Asked user about database preference?
39- [ ] Chosen database for THIS context?
40- [ ] Considered deployment environment?
41- [ ] Planned index strategy?
42- [ ] Defined relationship types?
43 
44---
45 
46## Anti-Patterns
47 
48❌ Default to PostgreSQL for simple apps (SQLite may suffice)
49❌ Skip indexing
50❌ Use SELECT * in production
51❌ Store JSON when structured data is better
52❌ Ignore N+1 queries
53