Dim conn As New System.Data.OleDb.OleDbConnection
 
        conn.ConnectionString = _
        "Provider=Microsoft.Jet.OLEDB.4.0;Data source=" & _
        "C:\myDB.mdb"
 
        Dim cmd As String
        Dim maxId As Integer
 
        Try
            conn.Open()
 
            cmd = "SELECT id FROM myTable"
            OleDbCommand1.CommandType = CommandType.Text
            OleDbCommand1.CommandText = cmd
            OleDbCommand1.Connection = Conn
            maxId = CType(OleDbCommand1.ExecuteScalar(), Integer)
        Catch ex As Exception
            MessageBox.Show("DB konnte nicht geöffnet werden!")
        Finally
            conn.Close()
        End Try