Date: Mon, 22 Mar 2004 17:25:44 +0100
From: Erik Thiele <erik@thiele-hydraulik.de>
To: Stephan Szabo <sszabo@megazone.bigpanda.com>
Cc: achill@matrix.gatewaynet.com, pgsql-sql@postgresql.org
Subject: Re: special integrity constraints
Message-Id: <20040322172544.0a9b34d4.erik@thiele-hydraulik.de>
In-Reply-To: <20040322061854.W56073@megazone.bigpanda.com>
References: <20040322102031.6a6f0b77.erik@thiele-hydraulik.de>
	<Pine.LNX.4.44.0403221212500.31407-100000@matrix.gatewaynet.com>
	<20040322112659.4553df76.erik@thiele-hydraulik.de>
	<20040322061854.W56073@megazone.bigpanda.com>
Organization: Thiele-Hydraulik
Mime-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit

On Mon, 22 Mar 2004 06:21:28 -0800 (PST)
Stephan Szabo <sszabo@megazone.bigpanda.com> wrote:

> 
> On Mon, 22 Mar 2004, Erik Thiele wrote:
> 
> > On Mon, 22 Mar 2004 12:13:29 +0200 (EET)
> > Achilleus Mantzios <achill@matrix.gatewaynet.com> wrote:
> >
> > > O kyrios Erik Thiele egrapse stis Mar 22, 2004 :
> > >
> > > Did you check out the DEFERRABLE option on the constraint?
> > >
> >
> > DEFERRABLE
> > NOT DEFERRABLE
> >
> > This controls whether the constraint can be deferred. A constraint that
> > is not deferrable will be checked immediately after every command.
> > Checking of constraints that are deferrable may be postponed until the
> > end of the transaction (using the SET CONSTRAINTS command). NOT
> > DEFERRABLE is the default.
> >
> > !!!! Only foreign key constraints currently accept
> > this clause. All other constraint types are not deferrable. !!!!
> >
> > my constraint is not a foreign key constraint....
> 
> However, foreign keys are implemented using "constraint triggers". They're
> really not documented much (because they're a not really separately
> supported implementation detail), but you can theoretically make
> triggers that are deferred to immediately before commit time.

could you paste some code?


create table a (x integer);

create or replace function alwaysfail() returns opaque as '
begin
  raise exception ''no no i dont want to'';
end;
' language 'plpgsql';

MAGIC COMMAND INSERT HERE, INSTALL CALL OF alwaysfail() ON
MODIFICATION OF TABLE a AT COMMIT TIME;

begin transaction;

insert into a values(4);
(ok)
insert into a values(10);
(ok)
commit;
(no no i dont want to)


is that possible?

cu
erik


-- 
Erik Thiele