Python Database Integration

Set up database integration for my Python project:

Database: [PostgreSQL/MySQL/SQLite/MongoDB]
Framework: [Django/Flask/FastAPI/Standalone]
ORM preference: [SQLAlchemy/Django ORM/Tortoise/Raw SQL]

Requirements:
- Models: [DESCRIBE YOUR DATA MODELS]
- Relationships: [ONE-TO-MANY/MANY-TO-MANY/etc.]
- Migrations: [YES/NO]
- Connection pooling: [YES/NO]

Provide:
1. Connection setup and configuration
2. Model definitions
3. Relationship mapping
4. CRUD operations
5. Complex queries
6. Transactions
7. Migration scripts
8. Connection pooling
9. Async support
10. Query optimization
11. Testing with test databases
12. Backup and restore scripts