relational-database - 客户和商品之间的关系是否正确？

Question

It is known about each employee of the shipping company what their first and last names are, their age, residence address, place of birth, correspondence address, e-mail.

Each employee who is a driver has one of the cars at the disposal. It is known about the car what make it is, what engine it has, when it was manufactured, etc.

Each car has a vehicle card, which contains information on failures, services, repairs, etc.

Shipping company has its customers and gathers the following information about them: first and last names, address, telephone no.

Customers commission the company the shipping of commodities. About commodities the following information is known: quantity, weight, address and date of shipping.

Customer can commission the shipping of more than one commodity. It is also known what the price of such a service is.

请查看我设计的这个 ER 图表。

我使用了“Look Across”Min-Max 表示法。

Answer 1

我会稍微更改图表以将运输订单显示为一个实体(目前在您的图表中它显示为一个关系)，如下所示:

每个客户可以有多个运输订单。

每个运输订单可以包含许多商品。

希望这可以帮助