商品销售：输入商品编号，输入购买数量，在库存信息表中查找相应产品，用库存数量减购买数量得到新库存数量， 如果是会员则商品价格使用会员价，将消费金额转换成积分记录在会员表-Inventory information table to find the corresponding products, with less inventory quantity Quantity get new inventory number, If commodity prices is a member