My view of FlyByNight's BDM (Itinerary, Segment and the like)
posted 10 years ago
I have an interesting idea regarding the interpretation of the Business Domain Model provided with FlyByNight.
I have read through this forum and it appears that the Segment - Flight - Equipment issue in the BDM caused a lot of trouble to many people.
Notice that what I am writing here is not "the" solution to this problem - we all know that this issue is subject to interpretation and there's no "correct" answer. Therefore I believe that my post is with accordance to the forum's guidelines.
As it turns out, the BDM makes perfect sense if it is looked at from the point of view of one particular moment in time. If looked at from that point of view, suddenly everything falls into place quite neatly:
1) In one instance of time, a customer has zero or more itineraries, and each itinerary is associated with one customer.
2) In one instance of time, a segment (interpreted as a "line" in the itinerary) is associated with one itinerary, and one itinerary is associated with 1 segment or more.
3) In one instance of time, a segment is indeed performed by one flight. Conversely, in one instance of time, one flight serves only one segment.
And so forth.
My question is: Is this a legal way to interpret a business domain model? Usually, when I am presented with a domain model, I am looking at it in a more generalistic way - however such a look renders the multiplicities in the BDM completely bizarre and useless (one can easily deduce that one flight serves only one customer. Follow the "..1" multiplicity from flight back to customer and figure it out).
What do you think would make more sense in the eyes of the examiner? The assumption that this BDM is time-centric, or the alternative way of trying to find hidden meanings and lost entities?
Will appreciate your comments.
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