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Message-ID: <4f4c2a010703291423y1fe42ff6rc425a78221f918a3@mail.gmail.com>
Date: Thu, 29 Mar 2007 17:23:02 -0400
From: "Jon Horsman" <horshaq@gmail.com>
To: "chester c young" <chestercyoung@yahoo.com>
Subject: Re: Foreign Unique Constraint
Cc: "sql pgsql" <pgsql-sql@postgresql.org>
In-Reply-To: <415536.67726.qm@web54310.mail.yahoo.com>
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References: <4f4c2a010703270621h5137a4e5rb515a9be9034a543@mail.gmail.com>
	<415536.67726.qm@web54310.mail.yahoo.com>

> use a pre-insert triggers - one for each table.  include something like

I ended up going this route and it seems to work.  Thanks for the help
from all. I figured i'd post the solution to the list so it shows up
when googled.  Also, if my solution can be simplfied i'd appreciate
knowing how.

This would be the trigger for table1 in my example.

CREATE FUNCTION function_name() RETURNS trigger AS '
        DECLARE
                result RECORD;
        BEGIN
                SELECT INTO result * FROM table2 WHERE extension=NEW.extension;
                IF FOUND THEN
                        RAISE EXCEPTION ''The extension % is already
in use'', NEW.extension;
                END IF;
                RETURN NEW;
        END;
' LANGUAGE plpgsql;

CREATE TRIGGER function_name BEFORE INSERT OR UPDATE ON table1 FOR
EACH ROW EXECUTE PROCEDURE function_name();

Again, thanks for the help.

Jon.