DELIMITER $$
CREATE OR REPLACE DEFINER=`root`@`localhost` PROCEDURE `vn`.`ticketRefund_beforeUpsert`(vRefundTicketFk INT, vOriginalTicketFk INT)
BEGIN
	DECLARE vAlreadyExists BOOLEAN DEFAULT FALSE;

	IF vRefundTicketFk = vOriginalTicketFk THEN
		CALL util.throw('Original ticket and refund ticket has same id');
	END IF;

	SELECT COUNT(*) INTO vAlreadyExists
		FROM ticketRefund
		WHERE refundTicketFk = vOriginalTicketFk;

	IF vAlreadyExists > 0 THEN
		CALL util.throw('This ticket is already a refund');
	END IF;
END$$
DELIMITER ;