杭州交通信息网冻屏:网上购书系统ER图
来源：百度文库 编辑：杭州交通信息网 时间：2024/04/29 02:59:52
2．用户登陆，验证用户名和密码；
3.浏览所有图书细节（图书号，书名，作者，出版社，单位，内容简介，折扣，种类）
4.查询
5．订购（放入购书蓝），未提交前允许取消；
6．提交购书单，未发货前可取消。
这是老师要我们做的一个网上购书系统，要我们先画出它的ER图，请哪位高人能给我画一下，不胜感激。
The ER Model of the Bookseller System
Entities:
Customer: Username, Password, Age, Sex, Salary, Speciality, Address(Street, City, Postcode), E-mail, Tel, Mobilephone, FavType;
VIPUser: Username, Totalprice, Discount;
NormalUser: Username, Totalprice, Discount;
Book: BookID, Bookname, Author{Name(Fname, MI, Lname)}, ISBN(_________), Year, Pub, Type, Price, Discount, Number;
Stock: BookID, Number;
Oos: BookID, Number;
BookType: TypeID, Type, Nmuber;
Relationships:
Sell: <Customer, Book>, M:N, PARTIAL/PARTIAL, SNoBook(Sno, Username, BookID), Number, Price, Totalprice, WayofSend, FixDate, SendDate, GetDate;
Has: <Book, BookType>, N:1, TOTAL/PARTIAL;
Some Assumptions/Clarifications:
• Not all customers necessarily buy books. Not all books are necessarily sold.
• Not all booktypes need necessarily be of books. However, all books must have a booktype and only one booktype.
• If there is no book with a particular name, the book will be in the out of stock set. The others are in the stock set.
• The customer who has paid over 200 Yuan will be in the VIP set. The others are in the normal set.
图传不上去……