Hi all,
I'm facing the following problem:
Area1 has got an 1:n relationship to Area2.
Area1, fl_id (PK) <----- Area2, fl_fk (FK)
1 : n
Now I want to ensure that this relationship will also be spatially.
I only want to have new geometry objects in table Area2, which are
within Area1 including the 1:n relationship.
(if that sounds bad, sorry for my poor english ;-)).
Example: Area2, fl_fk = 1 must be within Area1, fl_id = 1
-------------------
| Area1, fl_id = 1 |
| |
| ----------- |
| | Area2, | |
| | fl_fk = 1 | |
| ---------- |
| |
-------------------
The following trigger won't work.
CREATE OR REPLACE FUNCTION check_geom()
RETURNS "trigger" AS
$BODY$
BEGIN
IF (SELECT st_within(NEW.geometry, a.geometry) FROM Area1 a WHERE
a.fl_id = NEW.fl_fk) <> 1 THEN
RAISE EXCEPTION 'Geometry is not valid!';
RETURN NEW;
END IF;
END;
$BODY$
LANGUAGE 'plpgsql' VOLATILE;
ALTER FUNCTION check_geom() OWNER TO postgres;
CREATE TRIGGER trig_check_geom
BEFORE INSERT OR UPDATE
ON Area2
FOR EACH ROW
EXECUTE PROCEDURE check_geom();
Everytime I insert a geometry object into table Area2, regardless wether
it's within an polygon of Area1 or not, I get the exception.
Any help would be appreciated.
bye,
Johannes
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