DELIMITER $$
CREATE OR REPLACE DEFINER=`vn`@`localhost` FUNCTION `vn`.`buy_getUnitVolume`(vSelf INT)
	RETURNS int(11)
	DETERMINISTIC
BEGIN
/**
 * Calculates the unit volume occupied by a buy.
 *
 * @param vSelf The buy id
 * @return The unit volume in cubic centimeters
 */
	DECLARE vItem INT;
	DECLARE vPackaging VARCHAR(10);
	DECLARE vPacking INT;

	SELECT itemFk, packagingFk, packing
		INTO vItem, vPackaging, vPacking
		FROM buy
		WHERE id = vSelf;

	RETURN IFNULL(ROUND(item_getVolume(vItem, vPackaging) / vPacking), 0);
END$$
DELIMITER ;