Re: lastval()

From: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
To: Abhijit Menon-Sen <ams(at)oryx(dot)com>
Cc: pgsql-patches(at)postgresql(dot)org
Subject: Re: lastval()
Date: 2005-05-11 03:44:38
Message-ID: 200505110344.j4B3icX03053@candle.pha.pa.us
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Abhijit Menon-Sen wrote:
> At 2005-05-10 23:30:05 -0400, pgman(at)candle(dot)pha(dot)pa(dot)us wrote:
> >
> > > By the way, what would lastval() do if an insert trigger inserts
> > > a row into a table with another serial column?
> >
> > It fails, just like it would fail now if the trigger inserted into
> > the same table that used the trigger, or a rule.
>
> I don't understand what you mean. "Just like it would fail now"? It
> doesn't exist yet, how can it fail? And how would it know when to
> fail anyway, rather than return a wrong value?

Uh, if the table's sequence name is 'tab_x_seq', and you do
currval('tab_x_seq'), you will get the trigger or rule insert id in that
case.

So, currval() widens a problem we already have if the rule/trigger
inserts into the same table.

--
Bruce Momjian | http://candle.pha.pa.us
pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 359-1001
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