Room rate system - login optimization

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《 Personal edition of room charging system 》 Basically completed , mine U The code of layer is very, very messy . Basically D There are several functions in the layer ,B There are several functions in the layer ,U Layer use corresponding B Every function in the layer . For example, in login ,U Layer first uses a function check username And the user password Whether it is right , And then use “ Add user login record ” Function of . The following is the sequence diagram of login ：

Login business is relatively simple , But for the complicated process of getting on the computer ？U The layer should check whether the card is registered . Whether the remaining amount is sufficient , Whether the status of the card is in use . Whether the card is not online now , After passing this series of tests , Also check the student table to display student information and so on .

This results in U Layer has many functions , and B The coupling degree of the layer is too large . Now let's think back and forth about the functions of each of the three layers ：

The presentation layer （UI）： Collect user input information and operations , Present specific business data to users . Generally speaking, it is user interface , That is, what a user sees and gets when using a system .

Business logic layer （BLL）： Actions for detailed problems . It can also be said to be the operation of the data layer . Logical processing of data business . There are three main ways ： from UI Get user instructions and data from , Run business logic ; from DAL Get data in , In order to offer UI Show ; from UI Get user instructions and data from , adopt DAL Write to data source .

Data access layer （DAL）： The transactions of this layer directly operate the database , For the addition of data 、 Delete 、 changes 、 Search, etc. .

Under the guidance of the master , Changes have been made ：

U layer ：

' Sign in 
    Private Sub btnLogin_Click(sender As Object, e As EventArgs) Handles btnLogin.Click
        ' Check empty 
        If PublicFunction.IsEmptyText(Me) = True Then
            Exit Sub
        End If

        ' Instanced entity User, quote B layer 
        Dim euser As New Entity.User
        Dim euserRecord As New Entity.UserRecord
        Dim blogin As New BLL.LoginBLL

        Try
            ' Pass the information entered by the user to the entity 
            euser.ProuserID = txtUserID.Text.Trim
            euser.ProuserPwd = txtUserPwd.Text

            ' Feedback information after user verification 
            If blogin.Check(euser, euserRecord) Then ' Login successful 
                ''UserID and UserLevel Is a global variable , Other functions need to be used 
                UserID = euser.ProuserID.Trim  ' Go to space 
                UserLevel = euser.ProuserLevel.Trim ' Go to space 
                ' The main window shows 
                Me.Hide()
                frmMain.Show()
            Else
                MsgBox(" Login failed ！username or password Mistake .", vbExclamation, " System prompt ")                txtUserID.Focus()                Exit Sub            End If        Catch ex As Exception            MsgBox(" error ！", vbExclamation, " System prompt ")        End Try    End Sub

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B layer ：

Public Function Check(ByVal euser As Entity.User, ByVal euserRecord As Entity.UserRecord) As Boolean
        Dim dt As DataTable
        dt = iuser.QueryUser(euser)

        Try
            If dt.Rows.Count = 0 Then
                Return False
            Else 'username and password Input correct 
                euser.ProuserID = dt.Rows(0).Item(0) ' user ＩＤ
                euser.ProuserLevel = dt.Rows(0).Item(2) ' User level 

                ' Enter the information recorded by the user on the computer 
                euserRecord.ProuserID = euser.ProuserID
                euserRecord.ProuserLevel = euser.ProuserLevel
                euserRecord.ProloginTime = Now
                euserRecord.PrologoutTime = Now
                euserRecord.ProisOnline = 1  '1 It means online .0 Means not online 
                euserRecord.Procomputer = My.Computer.Name ' Get the current computer username
                ' Add user login record 
                Dim result As Integer
                result = iuser.AddUserRecord(euserRecord)

                If result <> 0 Then ' Successfully joined the user record 
                    Return True
                End If
            End If
        Catch ex As Exception
            Throw New Exception
        End Try
     
    End Function

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D layer ：

  ' How to find users 
    Public Function QueryUser(euser As Entity.User) As DataTable Implements IUser.QueryUser
        Try
            Dim strSQL As String = "select * from T_User where [email protected] and [email protected] "
            Dim params() As SqlParameter = {New SqlParameter("@userID", euser.ProuserID), New SqlParameter("@userPwd", euser.ProuserPwd)}
            Dim helper As New SqlHelper.sqlHelper
            Dim table = helper.GetDataTable(strSQL, CommandType.Text, params)
            Return table
        Catch ex As Exception
            Throw New Exception
        End Try
      
    End Function

    ' The user successfully logged in to UserRecord
    Public Function AddUserRecord(euserRecord As Entity.UserRecord) As Integer Implements IUser.AddUserRecord
        ' When each field is filled , The contents in the preceding brackets can be omitted 
        'Dim strSQL As String = "insert into T_UserRecord values(@userID,@level,@loginTime,@logoutTime,@computer,@isOnline)"
        Try
            Dim strSQL As String = "insert into T_UserRecord (userID,userLevel,loginTime,logoutTime,computer,isOnline)values(@userID,@level,@loginTime,@logoutTime,@computer,@isOnline)"

            Dim params() As SqlParameter = {New SqlParameter("@userID", euserRecord.ProuserID),
                                            New SqlParameter("@level", euserRecord.ProuserLevel),
                                            New SqlParameter("@loginTime", euserRecord.ProloginTime),
                                            New SqlParameter("@logoutTime", euserRecord.PrologoutTime),
                                            New SqlParameter("@computer", euserRecord.Procomputer),
                                            New SqlParameter("@isOnline", euserRecord.ProisOnline)}
            Dim helper As New SqlHelper.sqlHelper
            Dim intResult = helper.ExecuteNoQuery(strSQL, CommandType.Text, params)
            Return intResult
        Catch ex As Exception
            Throw New Exception
        End Try
       
    End Function

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Login sequence diagram after change ：

The two login sequence diagrams form a sharp contrast , So the user clicks “ Sign in ”button after ,U The layer is responsible for collecting user input username and password, Then just call one Check() Function to verify .B Layer handles business logic . First infer user information , If the input is correct, proceed to the next step and add the user's computer record .D Layer and database . Add, delete, modify, etc .U The layer doesn't know the detailed authentication user details . This decouples , Attend to each one's own duties .

Summary ： From the first computer room charging system last year . To today's personal version reconstruction . And the next cooperation reconstruction , Every step is a leap . At first we were purely process oriented , Now I have learned the three-tier architecture , Design patterns are used , But it is still very far away from object-oriented . We are moving forward step by step , This process is very important . It's like Tang Monk learning from the West , Suppose you can get the Sutra by turning the monkey king over . Then there will be no classic 《 Journey to the west 》 了 .

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