Handling database table dependencies

rubyonrails-talk
1

Hey,

thanks for reading this post. How do you handle dependencies? A really simple example: I've got a table called "entity" and another table, let's say, "entity_type". The entity types can be changed, of course, they also should be deletable, but only, if they are not used by some entities! How can I ensure this in Rails or directly in the DBMS (postgres)? Do I have to check it manually within a validate-method in the model?

Thanks for any suggestions!

Cheers, ms

2

Are you talking about a polymorphic association??

You can set that up simply enough in the models after doing a wee search on them,

May have some interesting insight into them, it would then be easy enough to create a method from a before_destroy callback to check if it is being used or not...

Cheers

Richard