Jeff Boes <jeff(at)endpoint(dot)com> writes:
> I'm trying to write a general-purpose trigger that will disallow updates
> on certain fields (I could probably do this in other ways, but I have a
> stubborn streak ...).
I think it's pretty much impossible to do this in plpgsql. You could do
it in the other PLs that support triggers, or in C. From a performance
standpoint I'd think you'd want to do it in C anyway. There are some
closely related example trigger functions in the contrib tree.
regards, tom lane