Question please help with concurrency violent

quangha

Member
Joined
Jan 30, 2010
Messages
16
Programming Experience
Beginner
the idea: I'm making a data entry program, there is a database contains text that need to be input. about 20 people will have to do the job( ofcourse there's login form ). they will input all text for the text file, then the second time, and the order is random. I've tried using a column in the access database to control the concurrent, but no use.
First, user's computer will check all the records, then choose a random empty, no lock record. after that, put a lock to it, modified the value then release the lock. But still no luck. Any body can help me ? Thanks in advance.
here is my code
VB.NET:
Public Class main
    Dim con As New OleDb.OleDbConnection
    Public ds As New DataSet
    Dim da, dausr As OleDb.OleDbDataAdapter
    Dim maxrow, maxrowusr, demcheck1, demcheck2, chia, sodu, chay As Integer
    Dim randnum As New Random()
    Dim check, ktlan1 As Boolean
    Dim mix, temp, num As Integer
    Dim randarray(10000) As Integer

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        'user gởi yêu cầu lấy từ DB, 1 vòng lặp check xem có bao nhiêu account chưa làm, mỗi account chưa làm đưa ID vào array
        'randomarray rồi gởi randarray(1) cho người đó làm, làm xong update. Nếu vòng lặp báo về ko còn account trống thì chuyển qua giai đoạn
        'nhập lần 2 ( có thể báo hoặc ko ) .
        'Next x
        Dim cb As New OleDb.OleDbCommandBuilder(da)
        If TextBox1.Text = "" Then
            ds.Tables("dentry").Rows(randarray(1)).Item(6) = 0
            da.Update(ds, "dentry")
        Else
            If demcheck1 > 0 Then
                ds.Tables("dentry").Rows(randarray(1)).Item(2) = Form1.hoten
                ds.Tables("dentry").Rows(randarray(1)).Item(3) = TextBox1.Text
                ds.Tables("dentry").Rows(randarray(1)).Item(6) = 0
            Else
                ds.Tables("dentry").Rows(randarray(1)).Item(4) = Form1.hoten
                ds.Tables("dentry").Rows(randarray(1)).Item(5) = TextBox1.Text
                ds.Tables("dentry").Rows(randarray(1)).Item(6) = 0
            End If
            da.Update(ds, "dentry")
        End If
        random()
        If demcheck1 = 0 And demcheck2 = 0 Then
            Exit Sub
        End If
        check = True
        ds.Tables("Dentry").Rows(randarray(1)).Item(6) = check
        da.Update(ds, "Dentry")
        Label2.Text = ds.Tables("Dentry").Rows(randarray(1)).Item(1)
        TextBox1.Text = ""
    End Sub
    Sub random()
        Dim dem, dem1 As Integer
        dem = 0
        dem1 = 0
        demcheck1 = 0
        demcheck2 = 0
        'con.ConnectionString = "provider = microsoft.jet.oledb.4.0;data source = C:\DBtemp\DE.mdb"
        'da = New OleDb.OleDbDataAdapter("select*from usr order by id", con)
        'con.Open()
        'da.Fill(ds, "usr")
        'con.Close()
        'maxrowusr = ds.Tables("usr").Rows.Count

        'nhap lan dau tien
        For i = 0 To maxrow - 1
            If IsDBNull(ds.Tables("dentry").Rows(i).Item(3)) = 0 Or ds.Tables("dentry").Rows(i).Item(6) = 1 Then
                Continue For
            Else
                demcheck1 = demcheck1 + 1
                dem = dem + 1
                randarray(dem) = i
            End If
        Next

        If demcheck1 = 0 Then
            For i = 0 To maxrow - 1
                If IsDBNull(ds.Tables("dentry").Rows(i).Item(5)) = 0 Or ds.Tables("dentry").Rows(i).Item(6) = 1 Then
                    Continue For
                Else
                    demcheck2 = demcheck2 + 1
                    dem1 = dem1 + 1
                    randarray(dem1) = i
                End If
            Next
        End If
        If demcheck1 = 0 And demcheck2 = 0 Then
            MsgBox("Da hoan thanh viec nhap lieu !")
            Exit Sub
        End If
        If demcheck1 > 0 Then
            num = demcheck1
            For x As Integer = 1 To num
                mix = randnum.Next(x, num + 1)
                temp = randarray(mix)
                randarray(mix) = randarray(x)
                randarray(x) = temp
            Next x
            ds.Tables("dentry").Rows(randarray(1)).Item(6) = 1
            da.Update(ds, "dentry")
            TextBox2.Text = ""

            For i = 1 To demcheck1
                TextBox2.Text = TextBox2.Text & " " & randarray(i)
            Next
            
        Else
            num = demcheck2
            For x As Integer = 1 To num
                mix = randnum.Next(x, num + 1)
                temp = randarray(mix)
                randarray(mix) = randarray(x)
                randarray(x) = temp
            Next x
            ds.Tables("dentry").Rows(randarray(1)).Item(6) = 1
            da.Update(ds, "dentry")
            TextBox2.Text = ""

            For i = 1 To demcheck2
                TextBox2.Text = TextBox2.Text & " " & randarray(i)
            Next
        End If

    End Sub

    Private Sub main_FormClosing(ByVal sender As Object, ByVal e As System.Windows.Forms.FormClosingEventArgs) Handles Me.FormClosing
        Dim cb As New OleDb.OleDbCommandBuilder(da)
        check = False
        ds.Tables("Dentry").Rows(randarray(1)).Item(6) = check
        da.Update(ds, "Dentry")
        Form1.Close()
    End Sub

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

        Label1.Text = "ユーザ : " & Form1.hoten
        con.ConnectionString = "provider = microsoft.jet.oledb.4.0;data source = " & Form1.dsDB.Tables("location").Rows(0).Item(1)
        dausr = New OleDb.OleDbDataAdapter("select*from usr order by id", con)
        da = New OleDb.OleDbDataAdapter("select*from Dentry order by id", con)
        Dim cb As New OleDb.OleDbCommandBuilder(da)
        con.Open()
        da.Fill(ds, "Dentry")
        dausr.Fill(ds, "usr")
        con.Close()
        maxrow = ds.Tables("Dentry").Rows.Count
        maxrowusr = ds.Tables("usr").Rows.Count
        random()
        If demcheck1 = 0 And demcheck2 = 0 Then
            Exit Sub
        End If
        check = True
        ds.Tables("Dentry").Rows(randarray(1)).Item(6) = check
        da.Update(ds, "Dentry")
        Label2.Text = ds.Tables("Dentry").Rows(randarray(1)).Item(1)
    End Sub
End Class

i will attach the database so that you can imagin the idea, column2, column3 is the name of the people who input, column3 and 5 is the text inputted, and column 6 is use for lock
 

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  • DE.zip
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