一个公司希望为其客户订购行为建立一个数据库。一个消费者可以有一个或多个订单，每个订单可以有一种或多种商品。每个订单有一张发票，可以通过多种方式来支付，例如支票、信用卡或现金。-A company wants its customers ordering behavior of building a database. A consumer can have one or more orders, each order can have one or more commodities. Each order has an invoice, you can pay through a variety of ways, such as checks, credit cards or cash.