I have managed to develop one solution using functions and triggers. Has
anyone got a better solution?
Gary
create unique index "compound_bays_unique_index" on compound_bays using btree
(co_id,cr_id,cb_id);
create or replace function compound_rows_range_check() returns trigger as
$proc$
DECLARE
BAYNO int4;
BEGIN
-- if changing compound or row fail
IF NEW.co_id <> OLD.co_id THEN
RAISE EXCEPTION 'cannot change compound id';
END IF;
IF NEW.cr_id <> OLD.cr_id THEN
RAISE EXCEPTION 'cannot change row id';
END IF;
SELECT cb_id into BAYNO from compound_bays where
co_id = NEW.co_id and
cr_id = NEW.cr_id and
cb_id > NEW.cr_length
order by cb_id desc
limit 1;
IF found THEN
RAISE EXCEPTION 'Cannot remove occupied bays: % > %',
BAYNO, NEW.cr_length;
END IF;
RETURN NEW;
END;
$proc$ LANGUAGE plpgsql;
CREATE TRIGGER compound_rows_range_check BEFORE UPDATE on compound_rows
FOR EACH ROW EXECUTE PROCEDURE compound_rows_range_check();
create or replace function compound_bays_range_check() returns trigger as
$proc$
DECLARE
ROWLENGTH int4;
BEGIN
SELECT cr_length into ROWLENGTH from compound_rows where
co_id = NEW.co_id and
cr_id = NEW.cr_id;
IF not found THEN
RAISE EXCEPTION 'Compound / Row not found';
END IF;
IF NEW.cb_id > ROWLENGTH THEN
RAISE EXCEPTION 'row length exceeded: % > %',
NEW.cb_id,ROWLENGTH;
END IF;
RETURN NEW;
END;
$proc$ LANGUAGE plpgsql;
CREATE TRIGGER compound_bays_range_check BEFORE INSERT OR UPDATE on
compound_bays
FOR EACH ROW EXECUTE PROCEDURE compound_bays_range_check();
--
Gary Stainburn
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