DB Schema

Design a database schema from requirements: model entities, apply normalization, produce an ER diagram, generate DDL SQL, and write migration files with up/down.

Purpose

Translate business requirements into a normalized relational database schema with ER diagram, DDL, migration files, and index recommendations.

Trigger

Apply when user requests:

• "design database", "create schema", "model database", "ER diagram"
• "create table", "add migration", "design tables", "normalize database"
• "設計資料庫", "建立 schema", "建立資料表", "ER 圖", "資料庫建模", "寫 migration"

Do NOT trigger for:

• Querying or analyzing existing data — no schema design needed
• ORM usage or query optimization — not a schema design task
• Performance tuning of existing queries without schema changes