ssd7 exercise7满分答案

代码片断： ============================================================================================================================ 1.In step1,we map all the entities types into tables and define their primary keys PKs and alternate keys AKs. ============================================================================================================================ S1 PUBLISHER(publisherID,Name,Address) S1 PK(publisherID) S1 AK(Name,Address) S1 BOOKTitle(ISBN,Author,Title,publisherID,Edition,DateofPublication,Price,BookDesc ription,Categories) S1 PK(ISBN) S1 CUSTOMER(CustomerID,CustomerName,MailingAddress,CreditNumber,EmailAddress,Phone Number) S1 PK(CustomerID) S1 SHIPMENT(Shipmentnum,Method,Date) S1 PK(Shipmentnum) S1 ORDER(OrderNumber,CustomerID, MethodShipment, ShippingDate, OrderTime(Date,Time), OrderItemID) S1 PK(OrderNumber) S1 FK(CustomerID)->CUSTOMER(CustomerID) S1 PROMOTION(PromotionNumber, DiscountPercentage, StartDate, EndDate) S1 PK(PromotionNumber) S1 CATEGORYS(CategoryID,subcategoryid) S1 PK(CategoryID) S1 AK(subcategoryid) 绝对正确，每一步都有详解。