Dim sql As String = "UPDATE pc SET IP = ?, " _
                & "ueberwachung_von = ?, ueberwachung_bis = ?, " _
                & "intervall = ?, wochentage = ? " _
                & "WHERE IP = ?"
                Dim cmd As New OleDb.OleDbCommand(sql, con)
                cmd.Parameters.Add("@IP", OleDbType.VarChar, 15, "IP").Value = _
                  IP
                cmd.Parameters.Add("@ueberwachung_von", OleDbType.VarChar, 8, _
                "von").Value = txt_von.Text
                cmd.Parameters.Add("@ueberwachung_bis", OleDbType.VarChar, 8, _
                "bis").Value = txt_bis.Text
                cmd.Parameters.Add("@intervall", OleDbType.VarChar, 8, _
                "Intervall").Value = txt_intervall.Text
                cmd.Parameters.Add("@wochentage", OleDbType.VarChar, 13, _
                "Tage").Value = txt_day.Text
                cmd.Parameters.Add("@IP2", OleDbType.VarChar, 15, "IP").Value = _
                IP
                cmd.CommandType = CommandType.Text