What about using an intermediary value such as -1;
update foo set a = -1;
update foo set b = old a value;
update foo set a = old b value;
Sort of thing?
Chris
> -----Original Message-----
> From: pgsql-sql-owner@postgresql.org
> [mailto:pgsql-sql-owner@postgresql.org]On Behalf Of Josh Berkus
> Sent: Friday, 17 May 2002 3:30 AM
> To: Stephan Szabo
> Cc: pgsql-sql@postgresql.org
> Subject: Re: [SQL] Constraint problem
>
>
>
> Stephan,
> > > I don't seem to be able to create a UNIQUE constraint as
> DEFERRABLE. Is
> this
> > > not supported?
> >
> > Not currently.
>
> Hmm ... my workaround didn't work. I need to impose a unique
> constraint on
> an INT column in a table, but make sure that the constraint isn't checked
> until the end of an UPDATE statement, so that I can swap values
> when I need
> to.
>
> How can I do this?
>
> --
> -Josh Berkus
>
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