Re: per-statement-level INSTEAD OF triggers

Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> On Mon, Aug 8, 2016 at 4:40 AM, Yugo Nagata <nagata(at)sraoss(dot)co(dot)jp> wrote:
>> I'm asking out of curiosity, do anyone know why we don't have
>> per-statement-level INSTEAD OF triggers? I looked into the
>> standard SQL (20xx draft), but I can't find the restriction
>> such that INSTEAD OF triggers must be row-level. Is there
>> any technical difficulties, or other reasons for the current
>> implementation?

> I think one problem is that the trigger wouldn't have any way of
> knowing the specifics of what the user was trying to do. It would
> just know the type of operation (INSERT, UPDATE, or DELETE). I guess
> that could be useful to someone, but not all that useful.

It might be more useful after we get the infrastructure that Kevin's been
working on to allow collecting all the updates into a tuplestore that
could be passed to a statement-level trigger. Right now I tend to agree
that there's little point.

regards, tom lane