Groups > comp.lang.java.programmer > #19554

Re: How to store and represent 1 objects relationship to other objects

From	David Lamb <dalamb@cs.queensu.ca>
Newsgroups	comp.lang.java.programmer
Subject	Re: How to store and represent 1 objects relationship to other objects
Date	2012-10-29 10:12 -0400
Organization	A noiseless patient Spider
Message-ID	<k6m2t4$hr8$1@dont-email.me> (permalink)
References	<23786bb4-22cc-4711-a172-8e5c7ce5375e@googlegroups.com> <k6etkf$ufg$1@dont-email.me> <7ae71496-be19-497a-b856-7333d3b4adf7@googlegroups.com> <p1vr88dc7f5g1roonesmrvhvnrjlpgdchj@4ax.com>

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On 28/10/2012 11:47 PM, Gene Wirchenko wrote:
> On Fri, 26 Oct 2012 14:51:49 -0700 (PDT), Lew <lewbloch@gmail.com>
> wrote:
>
> [snip]
>
>> If you further wish to guarantee that no 'LineItem' appears more than once, you'd likely use a 'Set'
>> instead of a 'List'. Unfortunately the JPA spec doesn't seem to allow 'SortedSet', but it seems that
>> the '@OrderBy' annotation hacks around that limitation.
>
>       Sets (in the mathematical sense) do not have order.  If you want
> to have an order, use a list.

Mathematically he's looking for an injective sequence -- one where there 
is an order but where no element occurs more than once. It's neither a 
simple list nor a simple set, so I'm not surprised that there's some 
sort of of "@OrderedSet" annotation grafted onto a conventional data 
structure.

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Thread

How to store and represent 1 objects relationship to other objects pat.trainor@gmail.com - 2012-10-26 11:40 -0700
  Re: How to store and represent 1 objects relationship to other objects Lew <lewbloch@gmail.com> - 2012-10-26 12:23 -0700
  Re: How to store and represent 1 objects relationship to other objects Daniele Futtorovic <da.futt.news@laposte-dot-net.invalid> - 2012-10-26 22:59 +0200
    Re: How to store and represent 1 objects relationship to other objects Lew <lewbloch@gmail.com> - 2012-10-26 14:51 -0700
      Re: How to store and represent 1 objects relationship to other objects Daniele Futtorovic <da.futt.news@laposte-dot-net.invalid> - 2012-10-27 00:48 +0200
        Re: How to store and represent 1 objects relationship to other objects Lew <lewbloch@gmail.com> - 2012-10-26 16:07 -0700
      Re: How to store and represent 1 objects relationship to other objects Gene Wirchenko <genew@ocis.net> - 2012-10-28 20:47 -0700
        Re: How to store and represent 1 objects relationship to other objects David Lamb <dalamb@cs.queensu.ca> - 2012-10-29 10:12 -0400

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