in the end, I believe one has to come up with one's own interpretation, and it'll be ok as long as it is coherent. XM
When the compiler's not happy, ain't nobody happy...
Joined: Sep 22, 2003
well thanks, finally a reply ! Meanwhile, I have inquired on airline forums about this. The final conclusion that I have drawn is that Segments and Flights are synonims in the AirlineIndustry standards.
So I'll stick to the standard BDM (1:1) and imagine that information is "split" between Segment and Flight.
Segment holds more abstract information (price, airport) and Flight holds more detailed information (date and time of departure, Equipment used)
This way, from the Itinerary I collect Segments (1:M) from Segment I collect the Flight (1:1) from Flight I collect the Equipment (1:1) from Equipment I collect the Seats (1:M)
sound reasonable ? regards Francesco
Joined: Mar 10, 2006
I'm thinking about something different. My thoughts:
Segment A segment is a line in the itinerary that represents a flight item, along with its seat number. I mean, not the full list of available flights (Flight class), just a mapping between the itinerary and its items (segments). Each segment is then related to one flight, beacuse each segment are the flight details for an entry in the Itinerary (Although a flight might be related to many segments, one per seat in the plane).
Flight Flight classes are the available list of flights, it's origins, destinations, flight number and timing. Each flight is related to an equipment, though an equipment is related to many flights (another potential incoherence of the BDM and/or my interpretation). Equipment & Seats Equipment are planes and seat are its seats. That's obvious, but the point is that both of these elements won't change unless the company buys new planes.
This is my interpretation. For example, if a customer bought a Pto. Rico -> New York route, and it has a connection in Miami it would be separated in two itinerary items (segments). The delicate thing is that under this approach, the flight number could not be the PK of a potential flight table, the key should be composed of the flight number along with its origin and destination.