• Post Reply Bookmark Topic Watch Topic
  • New Topic
programming forums Java Mobile Certification Databases Caching Books Engineering Micro Controllers OS Languages Paradigms IDEs Build Tools Frameworks Application Servers Open Source This Site Careers Other Pie Elite all forums
this forum made possible by our volunteer staff, including ...
Marshals:
  • Campbell Ritchie
  • Ron McLeod
  • Paul Clapham
  • Jeanne Boyarsky
  • Bear Bibeault
Sheriffs:
  • Rob Spoor
  • Henry Wong
  • Liutauras Vilda
Saloon Keepers:
  • Tim Moores
  • Carey Brown
  • Stephan van Hulst
  • Tim Holloway
  • Piet Souris
Bartenders:
  • Frits Walraven
  • Himai Minh
  • Jj Roberts

A question about part2

 
Greenhorn
Posts: 1
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Can someone tell me what is equipment?
Thank you!
 
Ranch Hand
Posts: 181
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
An airplane.
 
Greenhorn
Posts: 1
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Thank you Jun Hong!
 
Greenhorn
Posts: 7
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator

Originally posted by Jun Hong:
An airplane.


Then how could explain the 1-1 relationship?
an airplane could only be used for a flight? It seems unrealistic.
Thanks
 
author and jackaroo
Posts: 12199
280
Mac IntelliJ IDE Firefox Browser Oracle C++ Java
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Hi Dissip,
Welcome to JavaRanch.
I'll try and explain a way that this might work - you will have to decide for yourself whether this fits or not.
In the airline industry, they quite often change the type of plane for a given flight depending on the number of bookings. So even if you caught the same flight number every day between the same cities at the same time, you might get a different type of aircraft. For example a 747 holds roughly 400 passengers (it varies by 747 model number), whereas a DC-10 holds roughly 300 people - either might be used for the same route, depending on the number of passengers booked for a certain flight on a certain day.
Furthermore the seating types themselves can change on any given day (although this doesn't normally apply to the low cost airlines). So today's flight might have 9 first class seats, 30 business class seats, and 335 econonmy class seats. But tomorrow's flight on the same physical aircraft may have 6 first class seats, 20 business class seats, and 358 economy class seats - all dependant on what sort of bookings the airline has already taken and what their expected usage of the flights will be.
So, in a sense, each individual flight can be considered to have a unique aircraft.
Does this help?
Regards, Andrew
[ March 12, 2004: Message edited by: Andrew Monkhouse ]
 
dissip angler
Greenhorn
Posts: 7
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Thank you very much, Andrew.
And what's your opinion about the 1-1 relationship between the segment and the flight?
As I think a segment is a part of the itinerary reservation. And a flight is a trip of an airplane (equipment) from one city to another at specific date and time.
So it is reasonable that every segment correspond to 1 flight. But how could a flight just correspond just 1 segment (reservation).
(Although I tried to interpret the segment and flight as some other things, such as segment: the route between 2 cities, flight a series of trips of an airplane from one city to another, it seems there's always a contradiction in the multiplicity of the relationships.)
Thank you again and looking forward for your reply.
 
Ranch Hand
Posts: 101
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
I have the same problem ��� 3 week ago that have this problem ����
I thinks that relation 1-->1 not is correct���

I need help us ��
 
Put a gun against his head, pulled my trigger, now he's dead, that tiny ad sure bled
SKIP - a book about connecting industrious people with elderly land owners
https://coderanch.com/t/skip-book
reply
    Bookmark Topic Watch Topic
  • New Topic