// select "Modift mode"
        public void modifyMode()
        {
            string sql;

            string[] date;

            date = new string[3];
            date = past_day.ToString("yyyy-M-d").Split('-');
            sql  = QueryList.overlapMultiCheckSQL(date, past_h, past_m);
            connect.Open();
            SQLiteCommand    command = new SQLiteCommand(sql, connect);
            SQLiteDataReader reader  = command.ExecuteReader();

            if (!reader.Read())
            {
                MessageBox.Show("Can't find past data.");
                reader.Close(); connect.Close();
                return;
            }
            reader.Close();     connect.Close();

            // single alarm mode.
            if (checkBox_isMulti.Checked == false)
            {
                sql = QueryList.updateSQL(date, numericUpDown_hour.Value, numericUpDown_minute.Value, textBox_text.Text, checkBox_alarm.Checked, (int)past_h, (int)past_m);
                connect.Open();
                command = new SQLiteCommand(sql, connect);
                command.ExecuteNonQuery();
                connect.Close();
            }

            // multi alarm mode.
            else
            {
                DateTime temp_checkDay = new DateTime(dateTimePicker_start.Value.Ticks);
                int      dayCount      = (DateTime.Parse(dateTimePicker_end.Value.ToString("yyyy-M-d")) - DateTime.Parse(dateTimePicker_start.Value.ToString("yyyy-M-d"))).Days;

                for (int count = 0; count <= dayCount; count++, temp_checkDay = temp_checkDay.AddDays(1))
                {
                    date = new string[3];
                    date = temp_checkDay.ToString("yyyy-M-d").Split('-');
                    sql  = QueryList.updateMultiSQL2(date, numericUpDown_hour.Value, numericUpDown_minute.Value, textBox_text.Text, checkBox_alarm.Checked, past_h, past_m);

                    connect.Open();
                    command = new SQLiteCommand(sql, connect);
                    command.ExecuteNonQuery();
                    connect.Close();
                }
            }

            // refresh data
            refreshData();
            cmain.changeCalendar();
            cmain.calendarListRefresh();
            cmain.refreshAlarm();
        }