public String QueryItinerary(Transaction context, Customer customer)
        {
            var buf = new StringBuilder(1024);

            buf.Append(Flights.QueryReserved(context, customer));
            if (buf.Length > 0)
            {
                buf.Append(',');
            }
            buf.Append(Cars.QueryReserved(context, customer));
            if (buf.Length > 0)
            {
                buf.Append(',');
            }
            buf.Append(Rooms.QueryReserved(context, customer));

            return(buf.ToString());
        }