What is the theoretical basis for testing a database?

When testing a database, it is important to check several key aspects:

• Data integrity: checking constraints (such as primary keys, foreign keys, uniqueness) to ensure data does not violate business logic.
• Correctness of CRUD operations: creating, reading, updating, and deleting data should work correctly.
• Query performance: checking response times and query optimization, especially for complex JOINs and aggregate functions.
• Transactional consistency: verifying that transactions are executed atomically and data remains consistent in case of failures.
• Security: checking access rights, encryption, and protection against SQL injections.
• Backup and recovery: testing backup and data restoration mechanisms.

Example: you can write a test that attempts to insert a duplicate of a unique value and verify that the database returns an error.