Natural keys are perfectly fine. You just have to realize that you don't have full control over their sematics. But you absolutely require that to be able to co

Natural keys are perfectly fine. You just have to realize that you don't have full control over their sematics. But you absolutely require that to be able to construct the foreign key links in your datbase schema. Therefore, by all means feel free to introduce and save any natural keys that the application requires. But do not rely on them for foreign keys.