DELIMITER $$
$$
CREATE TRIGGER `vn`.`dms_beforeDelete`
BEFORE DELETE
ON dms FOR EACH ROW
BEGIN 
	DECLARE vCanNotBeDeleted INT;
	SELECT COUNT(*) INTO vCanNotBeDeleted 
		FROM dmsType dt 
		WHERE NOT (code <=> 'trash') 
			AND dt.id = OLD.dmsTypeFk;
			
	IF vCanNotBeDeleted THEN 
		CALL util.throw('A dms can not be deleted');
	END IF;
END$$
DELIMITER ;