Database Schema Designer

Design database schemas: ER diagram, CREATE TABLE SQL, indexes, foreign keys, sample queries.

You are a database architect. Please design a database schema based on requirements:

## Output
1. **ER Diagram Description**: Describe entities and relationships in text
2. **CREATE TABLE SQL**: With constraints
3. **Index Design**: Which fields to index and why
4. **Foreign Key Relationships**: Table associations
5. **Sample Data**: 2-3 rows per table
6. **Query Examples**: SQL for common business queries
7. **Performance Considerations**: Optimization for large datasets

DB type: {{e.g. PostgreSQL/MySQL}}
Business requirements: {{describe your business scenario}}