VB 怎样验证SQL数据表中的用户登录

窗体中两个textbox，一个是用户名：txtUsername，一个密码:txtPassword。
两个CommandButton，一个是提交:subm，一个是退出。
数据库表是：book数据库中的admin表。
admin表中有username和password
怎样去验证用户的登录？当登录成功，载入窗体Form2。
要具体的代码，十分感谢！

补充：数据库是SQL Server2000
		

答案：
先选用ADODC
'窗体1代码
Dim pnum As Integer
Private Sub Command1_Click()
                    Adodc1.RecordSource = "select * from Table_xxwhb where 用户名 ='" & Text1.Text & "'"
                    Adodc1.Refresh
                    If Adodc1.Recordset.RecordCount > 0 Then
                    '      Text2 = Mid(Md5_String_Calc(Text1), 1, 16)   '校对MD5
'''''''                    Txtpwd.Text = Mid(Md5_String_Calc(Txtpwd), 1, 32)
                    MPassword = Adodc1.Recordset.Fields("密码")
''                    user1 = Adodc1.Recordset.Fields("权限")
'                    user2 = Adodc1.Recordset.Fields("编号")
                   If Txtpwd.Text = MPassword Then                     '判断数据的密码是否正确
'                    UserName = Combo1.Text '用户名
'                    Userb = user2 '编号
'                    Usern = user1 '权限
                    Form2.Show
                    Unload Me
                  Else
                    If pnum < 3 Then 'pnum就是密码验证次数，当次数超过3次，系统会自动保护退出
                    pnum = pnum + 1
                    MsgBox "用户名或密码错误!", vbInformation, "错误次数：" & pnum
                    
                    'MsgBox "密码错误,请重新输入", , "登陆界面管理"
                    Txtpwd.Text = ""
                    Txtpwd.SetFocus
                    Else
                    MsgBox "密码错误次数超过上限,系统自动退出", , "登陆界面管理"
                    End
                   End If
                   End If
                   End If
 
'ADODC1中用的连接字符串
Provider=SQLOLEDB.1;Integrated Security=SSPI;Persist Security Info=False;Initial Catalog=Data_RKGL;Data Source=(local)         '具体要看你那边了
          
把下边的代码复制到记事本里，另存为: 工程1.vbp
'--------------------------------------------
Type=Exe
Reference=*\G{00020430-0000-0000-C000-000000000046}#2.0#0#..\..\..\..\WINDOWS\system32\stdole2.tlb#OLE Automation
Reference=*\G{2A75196C-D9EB-4129-B803-931327F72D5C}#2.8#0#..\..\..\..\Program Files\Common Files\system\ado\msado15.dll#Microsoft ActiveX Data Objects 2.8 Library
Form=Form1.frm
Module=Module1; Module1.bas
Form=Form2.frm
Startup="Sub Main"
HelpFile=""
Command32=""
Name="工程1"
HelpContextID="0"
CompatibleMode="0"
MajorVer=1
MinorVer=0
RevisionVer=0
AutoIncrementVer=0
ServerSupportFiles=0
VersionCompanyName="1"
CompilationType=0
OptimizationType=0
FavorPentiumPro(tm)=0
CodeViewDebugInfo=0
NoAliasing=0
BoundsCheck=0
OverflowCheck=0
FlPointCheck=0
FDIVCheck=0
UnroundedFP=0
StartMode=0
Unattended=0
Retained=0
ThreadPerObject=0
MaxNumberOfThreads=1
[MS Transaction Server]
AutoRefresh=1

把下边的代码复制到记事本里，另存为: Form1.frm
'--------------------------------------------
VERSION 5.00
Begin VB.Form Form1 
   Caption         =   "Form1"
   ClientHeight    =   3090
   ClientLeft      =   60
   ClientTop       =   450
   ClientWidth     =   4680
   LinkTopic       =   "Form1"
   ScaleHeight     =   3090
   ScaleWidth      =   4680
   StartUpPosition =   3  '窗口缺省
   Begin VB.TextBox txtPassword 
      Height          =   270
      Left            =   990
      TabIndex        =   3
      Top             =   1500
      Width           =   2895
   End
   Begin VB.TextBox txtUsername 
      Height          =   270
      Left            =   990
      TabIndex        =   2
      Top             =   870
      Width           =   2895
   End
   Begin VB.CommandButton cmdExit 
      Caption         =   "退出"
      Height          =   495
      Left            =   2760
      TabIndex        =   1
      Top             =   2280
      Width           =   1455
   End
   Begin VB.CommandButton cmdSubmit 
      Caption         =   "登录"
      Height          =   495
      Left            =   360
      TabIndex        =   0
      Top             =   2280
      Width           =   1455
   End
   Begin VB.Label Label2 
      Caption         =   "密  码:"
      Height          =   285
      Left            =   210
      TabIndex        =   5
      Top             =   1500
      Width           =   735
   End
   Begin VB.Label Label1 
      Caption         =   "用户名:"
      Height          =   285
      Left            =   210
      TabIndex        =   4
      Top             =   870
      Width           =   735
   End
End
Attribute VB_Name = "Form1"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False

P

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