Database Constraint Designer

Design constraints for this database schema:

**Tables:**
```sql
{{TABLE_SCHEMA}}
```

**Business Rules:** {{BUSINESS_RULES}}
**Data Validation Requirements:** {{VALIDATION_REQUIREMENTS}}
**Database System:** {{DATABASE_SYSTEM}}

Please provide:
1. Primary key constraints with rationale
2. Foreign key constraints with:
   - Referential actions (CASCADE, SET NULL, etc.)
   - Justification for each choice
3. UNIQUE constraints
4. CHECK constraints for business rules
5. NOT NULL specifications
6. DEFAULT values
7. Constraint naming conventions
8. Performance impact of constraints
9. Testing constraint violations
10. Error handling recommendations