Constraints ⇒ hide problems

The reality is that information entered into a database is imperfect because users are not omniscient and they make mistakes. Also updates can be asynchronous which can create temporary conflicts.

Imposing integrity constraints can mean the data always looks perfect, giving a false sense of security. What's the use of integrity if the data lacks fidelity?

The database provides no information about how often problems are occurring if it doesn't record conflicting or missing information.