Re: Foreign key trigger timing bug?

Stephan Szabo <sszabo(at)megazone(dot)bigpanda(dot)com> writes:
> Yeah. I really don't understand it, but it appears to me to be explicitly
> different in the spec for on delete cascade even compared to the rest of
> the referential actions.

>> One problem I see is, what do we do if the BEFORE
>> trigger then returns NULL (to skip the delete). The cascaded operations
>> are already done. Do we have to execute the cascaded deletes in a
>> subtransaction or do we disallow the skip in this case?

> I think we'd have disallow skipping. Especially since skipping would
> probably end up with a violated constraint.

That seems to me to be a sufficient reason to not follow the spec in
this respect. A BEFORE trigger should be run BEFORE anything happens,
full stop. I can't think of any good reason why the spec's semantics
are better. (It's not like our triggers are exactly spec-compatible
anyway.)

regards, tom lane