Message-ID: <50819898.9090508@caido.ro>
Date: Fri, 19 Oct 2012 21:14:48 +0300
From: Victor Sterpu <victor@caido.ro>
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To: pgsql-sql@postgresql.org
Subject: Trigger triggered from a foreign key
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I have this trigger that works fine. The trigger prevents the deletion 
of the last record.
But I want skip this trigger execution when the delete is done from a 
external key.
How can I do this?

This is the fk
ALTER TABLE focgdepartment
   ADD CONSTRAINT fk_focgdep_idfocg FOREIGN KEY (idfocg)
       REFERENCES focg (id) MATCH SIMPLE
       ON UPDATE NO ACTION ON DELETE CASCADE;

This is the trigger
CREATE FUNCTION check_focgdepartment_delete_restricted() RETURNS trigger 
AS $check_focgdepartment_delete_restricted$
BEGIN
     IF ( (SELECT count(*) FROM focgdepartment WHERE idfocg = 
OLD.idfocg)=1)
     THEN RAISE EXCEPTION 'Last record can not be deleted';
     END IF;
     RETURN OLD;
END;
$check_focgdepartment_delete_restricted$
LANGUAGE plpgsql;
CREATE TRIGGER focgdepartment_delete_restricted BEFORE DELETE ON 
focgdepartment FOR EACH ROW EXECUTE PROCEDURE 
check_focgdepartment_delete_restricted();


Thank you