.NET+SQL SERVER 2000图书管理系统流程图+功能图+ER+全套设计论文 第6页

CREATE TABLE manage

(

      manageid int(4) NOT NULL UNIQUE,

      Pass char(10) 

) ;

CREATE TABLE users

(

      userid int(4) NOT NULL UNIQUE ,

      username char(10) ,

      pass char(10) ,

      email char(50) ,

      phone char(10) ,

      address varchar(50) ,

      BookNum int(4) 

);

GO

4.8 创建触发器

创建关于书号和用户号的触发器，分别在BOOKINFO .USERS中修改bookid和userid时，在LENDINFO中也会有相应的修改。

CREATE TRIGGER BookidChange

ON BOOKINFO

AFTER UPDATE

AS

IF UPDATE(bookid)

  BEGIN

     DECLARE @book_id as int

     DECLARE @old_book_id as int

     SELECT @ book_id=bookid inserted

     SELECT @ old_book_id =bookid deleted

Update LENDINFO

SET LENDINFO.bookid=@ book_id

WHERE LENDINFO. bookid =@ old_book_id

END

CREATE TRIGGER UserIdChanges

ON USERS

AFTER UPDATE

AS

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