【正文】 rivate myConn As SqlConnection Private ds As DataSet Private myAdapter As SqlDataAdapter Protected WithEvents Button2 As Protected WithEvents Label1 As Protected WithEvents Label2 As Protected WithEvents TextBox1 As Protected WithEvents Label3 As Protected WithEvents TextBox2 As Protected WithEvents Login_trname As Protected WithEvents Login_trpassword As Private myCmd As SqlCommand Private Sub Page_Load(ByVal sender As , ByVal e As ) Handles 39。 If GetRowsNum(sqlstr) = 0 Then Return False Else Return True End If End Function Public Sub BindDBGrd(ByVal sqlstr As String, ByVal myDBGrd As DataGrid) If = Then () End If Fill(sqlstr) = (0).DefaultView () End Sub Public Sub BindDBGrd(ByVal sqlstr As String, ByVal myDBGrd As DataGrid, ByVal SortExp As Object) If = Then () End If Fill(sqlstr) Dim dv As DataView = (0).DefaultView = SortExp = dv () End Sub Private Sub BindGrid() If Not Session(sqlstr) Is Nothing Then Dim sqlstr As String = CType(Session(sqlstr), String) BindDBGrd(sqlstr, ResultGrid) Session(sqlstr) = sqlstr End If End Sub Private Sub button1_Click(ByVal sender As , ByVal e As ) Handles Dim sign As String = If = True Then sign = % End If Dim sqlstr As String = select * from BookInfo where 1=1 sqlstr += and + + like 39。private bind Public Function GetRowsNum(ByVal sqlstr As String) As Integer If = Then () End If Fill(sqlstr) Close() Return (0). End Function Public Function AllowBooking(ByVal UserID As String) As Boolean Dim sqlstr As String = select * from UserInfo,RoleInfo where = and AllowBooking=1 and UserID=39。pwd=123456。Database=library。CREATE TRIGGER BookidChangeON BOOKINFOAFTER UPDATEASIF UPDATE(bookid) BEGIN DECLARE book_id as int DECLARE old_book_id as int SELECT book_id=bookid inserted SELECT old_book_id =bookid deletedUpdate LENDINFOSET = book_idWHERE LENDINFO. bookid = old_book_idENDCREATE TRIGGER UserIdChangesON USERSAFTER UPDATEASIF UPDATE(userid) BEGIN DECLARE user_id as int DECLARE old_user_id as int SELECT user_id =userid inserted SELECT old_user_id = userid deletedUpdate LENDINFOSET LENDINFO. userid = user_idWHERE LENDINFO. userid = old_user_idEND五、 使用ER/STUDIO完成數(shù)據(jù)庫設計六、 代碼實現(xiàn) “圖書管理系統(tǒng)”的功能模塊圖系統(tǒng)主界面：Imports Imports Public Class searchN Inherits Private connectingstring As String Private myConn As SqlConnection Private ds As DataSet Private myAdapter As SqlDataAdapter Protected WithEvents HyperLink1 As Protected WithEvents radiobutton1 As Protected WithEvents dropdownlist1 As Protected WithEvents button1 As Private myCmd As SqlCommand Public Sub Open() () End Sub Public Sub Close() () End Sub Public Sub Fill(ByVal sqlstr As String) myAdapter = New SqlDataAdapter(sqlstr, myConn) ds = New DataSet (ds) End Sub Private Sub Page_Load(ByVal sender As , ByVal e As ) Handles 39。CREATE TABLE users ( userid int(4) NOT NULL UNIQUE , username char(10) , pass char(10) , char(50) , phone char(10) , address varchar(50) , BookNum int(4) )。 CREATE TABLE LendInfo( LendID int(4) NOT NULL UNIQUE , BookID int(4) NOT NULL UNIQUE , UserID varchar(50) NOT NULL UNIQUE , LendDate smalldatetime(4) , ReturnDate smalldatetime(4) , IsBack int(4) )。Create view book_nameAsSelect bookid,pubname,bookauthor,bookname,searchNOFROM BOOKINFOWHERE bookname=’ASP程序設計’；創(chuàng)建關于用戶名的視圖，因為查詢時需要綁定。CREATE TABLE users ( userid int(4) NOT NULL UNIQUE , username char(10) , pass char(10) , char(50) , phone char(10) , address varchar(50) , BookNum int(4) )。 CREATE TABLE LendInfo( LendID int(4) NOT NULL UNIQUE , BookID int(4) NOT NULL UNIQUE , UserID varchar(50) NOT NULL UNIQUE , LendDate smalldatetime(4) , ReturnDate smalldatetime(4) , IsBack int(4) )。位置:事務BOOKINFOUSERSMANGERLENDINFO 對數(shù)據(jù)庫建立索引，索引語句在SQL語句中。數(shù)字字典名字:圖書信息別名:描述:描述圖書館所有已錄入的書目信息及該書的庫存情況.定義:圖書號+圖書名+圖書作者+出版時間+索取號+價格+圖書條碼。3． 借閱信息表（LENDINFO）：ID、用戶ID、圖書ID、借閱時間、歸還時間、歸還與否?？紤]到系統(tǒng)的實際需求，系統(tǒng)至少需要四張數(shù)據(jù)庫表，具體如下：1． 圖書信息數(shù)據(jù)表（BOOKINFO）：用于圖書館的所有已錄入的書目信息，這是本系統(tǒng)最為關鍵的數(shù)據(jù)部分，包括圖書號、圖書名、圖書作者、出版時間、索取號、價格和圖書條碼。生命周期法（Life Cycle Meth