From: | Daniel Struck <struck(dot)d(at)retrovirology(dot)lu> |
---|---|
To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
Cc: | pgsql-bugs(at)postgresql(dot)org |
Subject: | Re: abnormal behaviour of a CHECK CONSTRAINT with a regular |
Date: | 2004-02-10 16:08:58 |
Message-ID: | 20040210170858.4cf42b6d.struck.d@retrovirology.lu |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-bugs |
> I don't see any bug here; it's just that CHECK constraints are applied
> after any BEFORE triggers are run. Since the triggers could change the
> data to be inserted, the reverse order would be insecure.
Ups, it did make some false assumptions.
Thank you for the clarification.
If I understood now correctly, first the type, then the trigger and last the check constraint is checked.
This makes it also impossible to change the type of a value by a trigger?
Say I would want to change the input of a user to a date, this wouldn't be possible, because in first instance the type is not a date.
Here is an example I tried out:
CREATE TABLE test(datum DATE);
CREATE OR REPLACE FUNCTION function_test()
RETURNS trigger
AS 'BEGIN
new.datum := (''15.06.'' || new.datum)::date;
RETURN new;
END;'
LANGUAGE plpgsql;
CREATE TRIGGER trigger_test
BEFORE INSERT OR UPDATE
ON test FOR EACH ROW
EXECUTE PROCEDURE function_test();
INSERT INTO test VALUES('2003');
Best regards,
Daniel
--
Retrovirology Laboratory Luxembourg
Centre Hospitalier de Luxembourg
4, rue E. Barblé
L-1210 Luxembourg
phone: +352-44116105
fax: +352-44116113
web: http://www.retrovirology.lu
e-mail: struck(dot)d(at)retrovirology(dot)lu
From | Date | Subject | |
---|---|---|---|
Next Message | Stephan Szabo | 2004-02-10 16:10:13 | Re: abnormal behaviour of a CHECK CONSTRAINT with a regular |
Previous Message | Tom Lane | 2004-02-10 15:38:40 | Re: abnormal behaviour of a CHECK CONSTRAINT with a regular expression when a trigger is added |