Re: Why are triggers semi-deferred?

I am trying to figure out whether there is a TODO item in this thread.

The basis of the discussion appeared to be whether we are honoring the
spec by executing before/after statement/row/constraint triggers
properly, and if we are not, is it desirable/significant if we break the
spec.

Which need changes?

Before | After
Statement |
Row |
Constraint

Does anyone have answers for these? I read the thread and don't 100%
understand it all.

---------------------------------------------------------------------------

Stephan Szabo wrote:
>
> On Mon, 5 May 2003, Tom Lane wrote:
>
> > Stephan Szabo <sszabo(at)megazone23(dot)bigpanda(dot)com> writes:
> > > Actually, I think from sql99's description, for after row triggers it
> > > should happen after the row is modified not after the statement as a
> > > whole (so given two 2 row updates in a function you'd get
> > > update1,row1 afterrow1-1 update1,row2 afterrow1-2,afterstatement1
> > > update2,row1 afterrow2-1 update2,row2 afterrow2-2,afterstatement2
> > > )
> >
> > [ scratches head ... ] That seems a useless definition. What is the
> > purpose of firing immediately after, rather than immediately before,
> > a row update? Wouldn't you want to wait till end of statement so you
> > know that the whole statement is in fact going to complete (and not
> > die at some later row)? What do you have immediately after the update
> > that you didn't have just before it?
>
> You're right, I'd misread "the trigger event" as being a row change for a
> row trigger (go figure). However, looking at it, then I'm not sure our
> before row trigger timing is correct then. It seems from 14.14 for a
> delete example that the timing is supposed to be something like:
>
> before trigger 1
> before trigger 2
> delete 1
> delete 2
> after trigger 1
> after trigger 2
>
> rather than:
> before trigger 1
> delete 1
> before trigger 2
> delete 2
> after trigger 1
> after trigger 2
>
>
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