Recently when I started using an add-on that uses persistant relations, I've started using them. I was wondering as I didn't need them untill now what funtionallity they add to your database, except for the fact that these relations are proposed automatically when you create a view or a dataenvironment for a form (which I prefer to do myself ...). I know they're are used by the RI builder too (which I don't use ..), but what I want to know, are they only what is called meta data or does the database act different when they are defined ?