What common mistake do developers make with Database assertions, why does the mistake cause problems, and what is the safer approach?

What common mistake do developers make with Database assertions, why does the mistake cause problems, and what is the safer approach? One recurring problem with database assertions is applying it without understanding the boundary it protects. Testing only the happy path and never verifying that an unauthenticated or unauthorized request is rejected. In addition, Database assertions confirm that important records were created, updated or deleted as expected. Safer engineering approach: keep the responsibility in the correct layer, use the framework's supported API, validate and authorize inputs, avoid hidden side effects, and verify the behavior with tests.