Re: Combination of Triggers and self-FKs produces inconsistent data

Josh Berkus <josh@agliodbs.com> writes:
> Tom Lane wrote:
>> This isn't a bug.  If you create triggers that prevent the RI actions
>> from being taken, it's your own problem.

> Huh?  Since when was it OK by us to have data which violates a declared
> FK under *any* circumstances?

You can't have your cake and eat it too, Josh.  If we make the RI
mechanism operate at a level underneath triggers, then we'll lose all
sorts of useful capability that people are depending on.  A couple of
examples:

* the ability to log table changes caused by RI cascades

* the ability to maintain row update timestamps when the update is
  caused by an RI cascade


> Where in our docs does it say that
> Foreign Keys are not enforced if the table has triggers on it?

It doesn't say that, because it isn't true.  What is true is that if you
make a trigger that prevents updates from happening, it breaks RI
updates as well as directly-user-initiated updates.  Either way, you're
going to need to fix the trigger.

            regards, tom lane