Database Schema Designer

Design a database schema for {APPLICATION_TYPE}.

Database: {DATABASE_TYPE}
Key entities: {ENTITIES}
Expected scale: {USERS/DATA_SIZE}
Main queries: {QUERY_PATTERNS}

Provide:
1. Entity-Relationship Diagram (text)
2. Table definitions with columns
3. Data types and constraints
4. Primary/Foreign keys
5. Indexes for optimization
6. Sample SQL creation scripts
7. Normalization level
8. Migration strategy