漫步在校园的小道上，不被南飞的大雁所吸引，不被飘香的丹桂所痴望，只为那飘落一地金黄色的杨树叶所驻足，金黄灿烂，让我流连忘返,如随波荡漾的小船，摇摇摆摆，把灰白色的水泥路点缀的如同天空一般，星星点点，慢慢地，慢慢地，盖住了道路，层层叠叠，给人一种优美，舒适的感觉，伴随着杨树叶子从夏天的斑斓色彩到秋天的色彩斑斓，机房收费系统也从一无所知到略懂一二，现在就上下机的问题，做个小小的总结。

        上机，用到两张表，第一张是Student_info ,第二张表示Online_info,下面用一张图来展示上机是要做哪些相应的判断：

             

   代码如下

             

Private Sub cmdOn_Click()  
    Dim strSQL As String, strSQL2 As String, strSQL3 As String  
    Dim strMsgText As String, strMsgText2 As String, strMsgText3 As String  
    Dim objRst As ADODB.Recordset, objRst2 As ADODB.Recordset, objRst3 As ADODB.Recordset  
      
    '让下机日期和时间，消费时间和金额为空  
    txtOutDate.Text = ""  
    txtOutTime.Text = ""  
    txtPayTime.Text = ""  
    txtPayMoney.Text = ""  
      
    If txtCardNo.Text = "" Then  
        '判断卡号是否为空  
        MsgBox "请输入卡号！", vbOKOnly, "警告!"  
        txtCardNo.SetFocus  
        Exit Sub  
    Else  
        If Len(txtCardNo.Text) > 10 Then  
            '判断输入卡号是否超过设定的长度，防止出错  
            MsgBox "卡号过长，请输入长度<10的卡号", vbOKOnly, "警告!"  
            txtCardNo.SetFocus  
            Exit Sub  
        End If  
        '查询数据库里学生基本信息表  
        Set objRst = New ADODB.Recordset  
        strSQL = "select * from student_Info where cardNo='" & Trim(txtCardNo.Text) & "'"  
        Set objRst = ExecuteSQL(strSQL, strMsgText)  
        If objRst.BOF And objRst.EOF Then  
            '判读该卡号是否存在  
            MsgBox "该卡号未注册!", vbOKOnly, "警告!"  
            txtCardNo.Text = ""  
            txtCardNo.SetFocus  
            Exit Sub  
        Else  
            '判断余额是否充足  
            If objRst.Fields(3) < GetLeastMoney() Then  
               MsgBox "余额只有" & objRst.Fields(3) & ",少于最少金额，请先充值！", vbOKOnly, "警告!"  
                Exit Sub  
            Else  
              
                '判断该卡号是否正在上机  
                Set objRst3 = New ADODB.Recordset  
                strSQL3 = "select * from online_Info where cardNo='" & Trim(txtCardNo.Text) & "' and outDate is null"  
                Set objRst3 = ExecuteSQL(strSQL3, strMsgText3)  
                If Not (objRst3.BOF And objRst3.EOF) Then  
                    Label1.Caption = "该卡正在上机!"  
                    txtCardNo.SetFocus  
                    Exit Sub  
                Else  
                  
                    '显示该卡号的一些基本信息  
                    txtStudentNo.Text = checkField(objRst.Fields(0))  
                    txtDepartment.Text = checkField(objRst.Fields(4))  
                    txtType.Text = checkField(objRst.Fields(14))  
                    txtStudentName.Text = checkField(objRst.Fields(1))  
                    txtSex.Text = checkField(objRst.Fields(7))  
                    txtOnDate.Text = Date  
                    'onTime = Time  
                    txtOnTime.Text = Time  
                    txtAllCash.Text = checkField(objRst.Fields(3))  
              
                    '将上机前的余额提出来，用于下机时计算余额  
                    'curAllCash = checkField(objRst.Fields(3))  
                    Label1.Caption = "欢迎光临！"  
              
                    '将该卡上机的信息填入到online_Info表里  
                    Set objRst2 = New ADODB.Recordset  
                    strSQL2 = "select * from online_Info "  
                    Set objRst2 = ExecuteSQL(strSQL2, strMsgText2)  
                    'objRst2.MoveLast  
                    objRst2.AddNew  
                    objRst2.Fields(0) = txtCardNo.Text  
                    objRst2.Fields(1) = txtStudentName.Text  
                    objRst2.Fields(2) = Date  
                    objRst2.Fields(3) = Time  
                    objRst2.Fields(4) = Null  
                    objRst2.Fields(5) = Null  
                    objRst2.Update  
                    '查询此时正在上机的人数。（可以直接加1）  
                    lblPeopleCount.Caption = GetPeopleCount()  
                    PeopleCount = GetPeopleCount()   '保存正在上机的人数  
                    objRst2.Close  
              
                    objRst.Close  
                End If  
            End If  
        End If  
    End If  
      
              
          
End Sub  

        下机，主要用到两张表，第一张Line_info,第二张以及Basicdata_info，同样的，下机也用一种图来表示：

              

   代码如下

           

    Private sub  codoff_click()
    Dim strSQL As String, strSQL2 As String, strSQL3 As String
    Dim strMsgText As String, strMsgText2 As String, strMsgText3 As String
    Dim objRst As ADODB.Recordset, objRst2 As ADODB.Recordset, objRst3 As ADODB.Recordset
    Dim intTime As Single
    Dim fixedRate As Single
    Dim AllMoney As Currency
    Dim pay As Currency
  
  
    If txtCardNo.Text = "" Then
        '判断卡号是否为空
        MsgBox "请输入卡号！", vbOKOnly, "警告!"
        txtCardNo.SetFocus
        Exit Sub
    Else
        If Len(txtCardNo.Text) > 10 Then
            '判断输入卡号是否超过设定的长度，防止出错
            MsgBox "卡号过长，请输入长度<10的卡号", vbOKOnly, "警告!"
            txtCardNo.SetFocus
            Exit Sub
        End If
    End If
    Set objRst = New ADODB.Recordset
    strSQL = "select * from student_Info where cardNo='" & Trim(txtCardNo.Text) & "'"
    Set objRst = ExecuteSQL(strSQL, strMsgText)
    If objRst.BOF And objRst.EOF Then
        '判读该卡号是否存在
        MsgBox "该卡号未注册!", vbOKOnly, "警告!"
        txtCardNo.Text = ""
        txtCardNo.SetFocus
        Exit Sub
          
    End If
    objRst.Close
    strSQL = ""
    strMsgText = ""
      
      
      
    Set objRst = New ADODB.Recordset
    strSQL = "select * from online_Info where cardno='" & Trim(txtCardNo.Text) & "' and outDate is null "
    Set objRst = ExecuteSQL(strSQL, strMsgText)
    If objRst.BOF And objRst.EOF Then
        '判断该卡是否正在上机
        Label1.Caption = "该卡没有上机！"
        txtCardNo.SetFocus
        Exit Sub
    Else
        '显示下机的一些信息
        txtOutDate.Text = Date
        outTime = Time
        txtOutTime.Text = outTime
          
        onTime = CDate(Format(objRst.Fields("onTime"), "hh:mm:ss"))
      
        txtCardNo.Text = checkField(objRst.Fields("cardNo"))
        txtStudentName.Text = checkField(objRst.Fields("studentName"))
        txtOnDate.Text = checkField(objRst.Fields("onDate"))
        txtOnTime.Text = checkField(objRst.Fields("onTime"))
          
        Set objRst3 = New ADODB.Recordset
        strSQL3 = "select * from student_Info where cardNo='" & txtCardNo.Text & "'"
        Set objRst3 = ExecuteSQL(strSQL3, strMsgText3)
        txtStudentNo.Text = objRst3.Fields("studentNo")
        txtDepartment.Text = objRst3.Fields("department")
        txtSex.Text = objRst3.Fields("sex")
        txtType.Text = "固定用户"
          
        '删除该记录，将此时信息填入online_Info表里
        objRst.Delete
        objRst.AddNew
        objRst.Fields(0) = txtCardNo.Text
        objRst.Fields(1) = txtStudentName.Text
        objRst.Fields(2) = txtOnDate.Text
        objRst.Fields("onTime") = txtOnTime.Text
        objRst.Fields(4) = txtOutDate.Text
        objRst.Fields("outTime") = txtOutTime.Text
        objRst.Fields(9) = "正常下机"
        'intTime = Val(txtOutTime.Text - txtOnTime.Text)
          
        '计算上机的时间
        intTime = (outTime - onTime) * 24 * 2
                  
         Set objRst2 = New ADODB.Recordset
         strSQL2 = "select * from basicDate_Info "
         Set objRst2 = ExecuteSQL(strSQL2, strMsgText2)
         '查询固定用户30分钟的费用
         fixedRate = Val(objRst2.Fields(0))
         If intTime < (GetPreparTime() / 30) Then
             '判断上机时间是否超过了准备时间，没超过则花费为0
             objRst.Fields("pay") = 0
             objRst.Fields("allCash") = GetAllMoney(txtCardNo.Text)
         Else
             If intTime <= (GetLeastTime() / 30) Then
                 '判断上机时间是否超过半个小时，没则当成已经上了30分钟
                 objRst.Fields("pay") = fixedRate
                 AllMoney = GetAllMoney(txtCardNo.Text) - fixedRate
                 objRst.Fields("allCash") = AllMoney     '将余额写入上机记录表里
                 WriteAllMoney txtCardNo.Text, AllMoney  '将余额写入学生基本信息表里
             Else
                 If intTime > Int(intTime) Then
                     intTime = Int(intTime) + 1
                 Else
                     intTime = Int(intTime)
                 End If
                 pay = fixedRate * intTime
                 objRst.Fields("pay") = pay
                 AllMoney = GetAllMoney(txtCardNo.Text) - pay
                 objRst.Fields("allCash") = AllMoney    '将余额写入上机记录表里
                 WriteAllMoney txtCardNo.Text, AllMoney  '将余额写入学生基本信息表里
             End If
         End If
           
         '显示消费的时间金额，和余额
         txtPayTime.Text = Format(outTime - onTime, "hh-mm-ss")
         txtPayMoney.Text = objRst.Fields(6)
         txtAllCash.Text = GetAllMoney(txtCardNo.Text)     '- objRst.Fields(6)
         Label1.Caption = "欢迎下次再来!"
           
         objRst.Fields(7) = txtAllCash.Text    '将余额写到online_Info表里
           
         lblPeopleCount.Caption = GetPeopleCount()  '显示正在上机人数
         PeopleCount = GetPeopleCount()
         objRst.Update
          
         objRst.Close
         objRst2.Close
         objRst3.Close
           
    End If
End Sub

         做系统最关键的问题就是思路，对整个系统的把控，知道第一步该怎么做，接下来该怎么做，一步一步走下去，方能水到渠成......