How do you ensure data integrity 

To ensure data integrity, you can:

1. **Use Constraints:** Implement primary keys, foreign keys, unique constraints, and check constraints in your database to enforce data validity.

2. **Normalization:** Organize the database into normal forms to reduce redundancy and dependency.

3. **Validation Rules:** Apply validation rules at the application and database level to ensure data accuracy and consistency.

4. **Transactions:** Use transactions to ensure that a series of database operations are completed successfully before committing the changes.

5. **Access Controls:** Restrict data access and modifications to authorized users only to prevent unauthorized changes.