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
