Problem when insert a record into microsoft access 2007 in vb.net

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VB

I've some problem in execute the record in vb.net. I'm using microsoft access 2007 as database.

I run my project and insert a record, I press the button "save" and my record shown in gridview, then I stop running my project.
When I run the project again, the record that I just insert in gridview was gone.

What's the problem??

This my syntax:

Imports System.Data
Imports System.Data.OleDb
Public Class OlahData
    Dim con As OleDbConnection
    Dim cmd As OleDbCommand
    Dim reader As OleDbDataReader
    Dim constring As String
    Dim SqlString As String
    Dim numAffected As Integer
    Private Sub OlahData_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        constring = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & My.Application.Info.DirectoryPath & "/FKIP.mdb ;Persist Security Info=True"
        con = New OleDbConnection(constring)
        con.Open()
    End Sub

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        SqlString = "Insert Into MataKuliah values ('" & id.Text.Trim & "','" & nama.Text.Trim & "','" & jurusan.Text.Trim & "','" & Val(sks.Text) & "')"
        cmd = New OleDbCommand(SqlString, con)
        numAffected = cmd.ExecuteNonQuery
        MessageBox.Show(numAffected.ToString & "record berhasil di simpan")
    End Sub
    
    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        Dim ConnStr As String = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & My.Application.Info.DirectoryPath & "/FKIP.mdb;"
        Dim Conn As OleDbConnection
        Dim Ds As DataSet
        Dim Da As OleDbDataAdapter
        Dim SQL As String = "Select * From MataKuliah"
        Try
            Conn = New OleDbConnection(ConnStr)
            Ds = New DataSet
            Da = New OleDbDataAdapter(SQL, Conn)
            Da.Fill(Ds, "MataKuliah")

            gridview.DataSource = Ds.Tables("MataKuliah")
            gridview.Dock = DockStyle.Fill
        Catch
            MessageBox.Show("tabel tidak dapat ditampilkan....!", "Database error", MessageBoxButtons.OK, MessageBoxIcon.Exclamation)
            Me.Close()
        End Try
    End Sub    
End Class

[edit]Code block added, "Ignore HTML..." option deselected - OriginalGriff[/edit]