Sergey Konoplev wrote:
> There is an oddity (or a bug) in situation with returning null before
> delete trigger and referential integrity in PG 8.3.3. I tryed to find
> a solution in Google and PG documentation and have noticed nothing
> useful.
[snip]
> CREATE OR REPLACE FUNCTION tr_stop()
> RETURNS trigger AS
> $BODY$begin
> return null;
> end;$BODY$
> LANGUAGE 'plpgsql' VOLATILE;
>
> CREATE TRIGGER tr_stop
> BEFORE DELETE
> ON table2
> FOR EACH ROW
> EXECUTE PROCEDURE tr_stop();
[snip]
> Now comming to a head. As I supposed earlier, deletion from table1 has
> to be prevented by referential integrity when the trigger prevents
> deletion of refered row from table2. But it doesn't.
[snip]
> Will you explain me please why PG behave so cos IMHO it's a bit
> illogical. Thanx.
Your trigger doesn't prevent deletion, it just skips the row(s) in
question from being affected. Raise an exception if you want to abort
the transaction.
See the manual - triggers chapter and plpgsql chapter for more details.
--
Richard Huxton
Archonet Ltd
