I have found out the hard way that foreign keys are indexed by default in some implementations including MySQL innodb. Not in oracle. My experience has been th

I have found out the hard way that foreign keys are indexed by default in some implementations including MySQL innodb. Not in oracle. My experience has been the opposite of yours -- I've heard of disabling foreign keys in production only for performance reasons, but not the other way around. I like them turned on all the time as well. Valuable safety rail