问题
I'm not quite sure how to approach this problem:
- Price for one-way trips is different than price for round trip itineraries.
In the backend, I have a table for storing the itinerary (which yields an id). I have another pricing table, which defines what is the price of this id from startDate to endDate.
My itinerary table can only represent information for one way travel. How do I model round trip itineraries ?
One way to deal with this was:
have another column in the table: returnId
if returnId = -1 -> one way trip else returnId = id to its complimentary itinerary
for e.g. A -> B is a roundtrip itinerary & C -> D is a one way trip;
It would look something like this:
Id | Departure | Arrival | ReturnId
1 | A | B | 3
2 | C | D | -1
3 | B | A | 1
In this case pricing table
Id | StartDate | EndDate | Price
1 | Jan 1, 2012 | Dec 10,2012| 150.00
3 | Jan 1, 2012 | Dec 10,2012| 150.00
2 | Jan 1, 2012 | Dec 10,2012| 100.00
I'd like to hear thoughts/suggestions on this design ?
EDIT:
I added a related question and I think the answer to this problem will have to cater to both the requirements.
One thing, I'd like to mention is..the price for a round trip is specified as a unit and not individual components from A->B and back, B->A.
Similarly, if there are multiple segments in a trip, price is defined for the complete trip and not individual segments.
回答1:
Rather than adding a self join like that, I would have a Trip table which contains the one-to-many mapping of Trip to Itinerary (where 1 trip consists of multiple itineraries). This way, a trip can have more than 2 legs..
Something like:
Trip_Itineraries
TripId | ItineraryId
1 | 1
1 | 2
2 | 3
Itinerary
ItineraryId | Departure | Arrival
1 | A | B
2 | B | A
3 | C | D
Pricing
ItineraryId | StartDate | EndDate | Price
1 | Jan 1, 2012 | Jul 10,2012 | 100.00
2 | Jul 1, 2012 | Dec 10,2012 | 100.00
2 | Jul 1, 2012 | Dec 10,2012 | 150.00
Then you can do:
SELECT T.TripId, sum(P.price)
FROM Trip_Itineraries T INNER JOIN Pricing P ON T.ItineraryId = P.ItineraryId
GROUP BY T.TripId
to get the total price for the trip..
回答2:
Blended the two answers and came up with this:
Journey:
- journeyId
- baggage policy
- misc
Segment:
- segmentId
- journeyId (FK)
- segment info
Price:
- journeyId
- startDate
- endDate
- price
Journey
Jid | baggage | misc
1 | "baggage policy1" | "round trip A->B"
2 | "baggage policy2" | "one-way C->D"
3 | "baggage policy3" | "one-way E->H with a hop in F, followed by G to H"
Segment
Id | Jid | Dep | Arrival
1 | 1 | A | B
2 | 1 | B | A
3 | 2 | C | D
4 | 3 | E | F
5 | 3 | F | G
6 | 3 | G | H
Price
JourneyId | StartDate | EndDate | Price
1 | Jan 1, 2012 | Dec 10,2012| 150.00
3 | Jan 1, 2012 | Dec 10,2012| 150.00
2 | Jan 1, 2012 | Dec 10,2012| 100.00
Thoughts ?
来源：https://stackoverflow.com/questions/9017881/how-do-i-design-return-travel-itinerary-vs-one-way-itinerary