Part 2 - Doubt about the meaning of "Segment"

[Eduardo Rodrigues]

Hi guys...
I'm with a doubt, I think many people too...

The Segment is a reservation in a flight or a possible route???

If a Segment is a reservation in a flight then the relationship between Segment and Flight is correct (1 to 1).

But if a Segment is a possible route then many Flights can cover the route (Flights VAR001, VAR002 and VAR003 covers the route between city A and B), then the relationshipt between Segment and Flight should be * - 1 (Many flights covers one route)...

I'd like the opinions from the forums guru's...

Thank you so much!!!

[Joyce Lee]

I follow the airline definition: A flight segment is defined as one takeoff and one landing on an itinerary. For example, if you want to travel from country A to country C and there's stopoever at B (A->B->C), there'll be two segments reflected on the itinerary. The route is A to C.

So 1 segment is assoicated to 1 flight. But in my opinion, 1 flight can be associated to more than 1 segment.

Search for "segment" at the following articles:
http://vacations.traveltime.com/c/17/17580/1796569_17580.htm
http://www.goerie.thinkhost.com/fare/terms.html

Joyce
[ June 20, 2004: Message edited by: Joyce Lee ]

[Eduardo Rodrigues]

Thank you so much Joyce...

[Peter Bergoff]

Awesome site Joyce - that was my thought about segment v. flight too.

[S. Ganapathy]

For example, if you want to travel from country A to country C and there's stopoever at B (A->B->C), there'll be two segments reflected on the itinerary. The route is A to C.

So 1 segment is assoicated to 1 flight. But in my opinion, 1 flight can be associated to more than 1 segment.

Passenget p1 wish to travel from country A to country B.
There are many alternatives.
One is directly from A --> C
Second is from A --> B --> C, using the same flight.
Third is from A --> D --> C, changinf flight at D.
A --> B --> C is called segment, or
A --> D --> C is called segment or leg?
Thanks in advance.
Regards,
Ganapathy., S

[Eduardo Rodrigues]

Ok, here is my interpretation...

Taking the example from Ganapathy:

One is directly from A --> C (lets call this FLIGHT001)
Second is from A --> B --> C, using the same flight (lets call this FLIGHT002)
Third is from A --> D --> C, changinf flight at D(lets call this FLIGHT003)

FLIGHT001 has only one Segment(A to C , lets call Segment 01)
So the passenger will need only one Reservation (to the Segment 01 from the FLIGHT001)

FLIGHT002 has two Segments (A to B called Segment 01 AND B to C called Segment 02)
So the passenger will need two Reservartions (one for the Segment 01 and anotehr one for the Segment 02, both relationed to the FLIGHT002)...


For the FLIGHT003 is the same idea of FLIGHT002

Please, guys, comments???

Bye
[ June 28, 2004: Message edited by: Eduardo Rodrigues ]

[Dave Patterson]

I follow the airline definition: A flight segment is defined as one takeoff and one landing on an itinerary. For example, if you want to travel from country A to country C and there's stopoever at B (A->B->C), there'll be two segments reflected on the itinerary. The route is A to C.

So 1 segment is assoicated to 1 flight. But in my opinion, 1 flight can be associated to more than 1 segment.

If the business domain model states a 1 to 1 relationship between segments and flights then:

Each segment has one and only one flight.
Each flight has one and only one segment.

By providing an architecture that changes this multiplicity you could argue that you are providing a more flexible solution - it still permits 1 flight to 1 segment and vice versa. However, if functionality is not strictly required so you must decide whether the additional complexity is justified.

Hope this helps.

Dave Patterson.

[Parag Doshi]

My initial confusion was with the definition of the term 'Flight'.
It is used at 2 different levels in the specification. First, is when you are searching for flights. This is at a more general (logical) level, where you want to go from Point A to Point B. The second level is the actual flight which can take u there, which might have zero or more halts. These actual flights (segments) have seat #, equipment etc associated with it.
so, for example. you want a flight from NYC to SFO. Now, this is a logical flight as there are actual flights which can take u there. for example. there can be atleast a couple of combinations:
1. Direct flight - NYC - SFO
2. One stop - NYC - Dallas & Dallas - SFO

These 2 above mentioned flights would have actual seats and equipment etc. The logical searched flight wouldnt have any seats. So a logical flight could be from NYC - SFO, but in actuality it could take 2 segments (NYC-Dallas, Dallas-SFO) to complete that flight.

I guess as they have shown the segment-flight as a 1-1 relationship, I am forced to think of some other ways to associate a flight (NYC-SFO) to its actual segments (with zero or more halts).

Does anyone also experience such confusion or am I the only one grappling with the meaning of 'flight'.


Thanks,
Parag

[Ajith Kallambella]

I encourage everyone taking part in this thread to read our position on discussing part2 assignment related issues.

Thanks!

[Joyce Lee]

My interpretion of a flight is ...
Each flight has a unique flight number and this flight is scheduled by particular airline. Let's say, a customer wants to travel from A to C, and there's a stopover/transit at B. Two scenarios:

Scenario 1:
A->B and B->C have two different flight numbers. Hence two segments are reflected on the itinerary.

Scenario 2:
A->B and B->C have same flight numbers. Hence 1 segment is reflected on the itinerary.

Take a look at these links at the flyertalk forum:
http://www.flyertalk.com/forum/showthread.php?t=321880&highlight=segment
http://www.flyertalk.com/forum/showthread.php?t=60028&highlight=segment
http://www.flyertalk.com/forum/showthread.php?t=28703&highlight=segment
http://www.flyertalk.com/forum/showthread.php?t=107392&highlight=segment
http://www.flyertalk.com/forum/showthread.php?t=158230&highlight=segment
http://www.flyertalk.com/forum/showthread.php?t=117457&highlight=segment
http://www.flyertalk.com/forum/showthread.php?t=41312&highlight=segment

Joyce
[ July 02, 2004: Message edited by: Joyce Lee ]