Actually, at least in some cases, PG does short-circuit logic:
create function seeme() returns bool as ' begin raise notice ''seeme''; return true; end'
language plpgsql;
joel@joel=# select false and seeme();?column?
----------f
(1 row)
joel@joel=# select true and seeme();
NOTICE: seeme?column?
----------t
(1 row)
In your case, the problem is short-circuiting a test, it's that the full
statement must be parsed and prepared, and it's probably in this stage that
the illegal use of old. in an insert jumps up.
HTH.
Joel BURTON | joel@joelburton.com | joelburton.com | aim: wjoelburton
Knowledge Management & Technology Consultant
> -----Original Message-----
> From: pgsql-hackers-owner@postgresql.org
> [mailto:pgsql-hackers-owner@postgresql.org]On Behalf Of Louis-David
> Mitterrand
> Sent: Tuesday, May 28, 2002 3:21 AM
> To: pgsql-hackers@postgresql.org
> Subject: [HACKERS] wierd AND condition evaluation for plpgsql
>
>
>
> Hi,
>
> I just noticed plpgsql evaluates all AND'ed conditions even if the first
> one fails. Example:
>
> elsif TG_OP = ''UPDATE'' and old.type_reponse = ''abandon''
>
> This will break stuff if the trigger is used on INSERT as
> "old.type_reponse" will be substituted and return an error.
>
> Shouldn't plpgsql shortcut AND conditions when a previous one fails, as
> perl does?
>
> --
> OENONE: Quoi ?
> PHEDRE: Je te l'ai prédit, mais tu n'as pas voulu.
> (Phèdre, J-B Racine,
> acte 3, scène 3)
>
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