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Re: Hibernate foreign key as primary key

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On 08/08/11 03:14, Robert Klemme wrote:
> On 07.08.2011 18:45, Frank Langelage wrote:
>> On 07.08.11 13:38, Lionel wrote:
>>> This may be a little off topic but I'm sure there are some experts in
>>> here.
>>>
>>> I'm having some troubles getting using a foreign key as a primary key.
>>> In this post I will use the most simple issue I'm having trouble with.
>>>
>>> Here's some snippets (pharmacy project):
>>>
>>> public abstract class AbstractDrugModel
>>> {
>>> private String name;
>>> private IntravascularDrug ivDrug;
>>> }
>>>
>>> public class IntravascularDrug
>>> {
>>> private AbstractDrugModel drug;
>>> }
>>
>> I can't help you with your problem but want to give a comment to this
>> mail.
>> Your class design does not make sense to me. You have a circular
>> reference between these two classes. Java allows this, but this is bad
>> design in my eyes.
>
> ... but very common for bidirectional relationships. If instances of
> both classes need to be able to navigate the relationship that design is
> the most efficient solution.

Yes. This is normal design. But read one.


>> And this might be the cause that hibernate cannot work with this design.
>
> Yes, might be.

My original relationship was actually unidirectional, there was no need 
for the IntravascularDrug to know about the AbstractDrugModel. However, 
to map the relationship in Hibernate somehow Hibernate needs to be able 
to get the primary key for IntravascularDrug which happens to be the 
primary key of AbstractDrugModel and is hence also a foreign key of 
IntravascularDrug.

I thought there might be more knowledge of hibernate on this forum, but 
based on the responses it seems it is too specific for this forum. I 
just wasn't getting responses to other questions on the Hibernate forum 
(and neither were many other people though there are a high number of 
posts) so I decided to try on my preferred medium :).

Thanks everyone for your input.

Lionel.

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Thread

Hibernate foreign key as primary key Lionel <lionelv@none.com> - 2011-08-07 21:38 +1000
  Re: Hibernate foreign key as primary key markspace <-@.> - 2011-08-07 07:07 -0700
  Re: Hibernate foreign key as primary key Robert Klemme <shortcutter@googlemail.com> - 2011-08-07 18:03 +0200
  Re: Hibernate foreign key as primary key Frank Langelage <frank@lafr.de> - 2011-08-07 18:45 +0200
    Re: Hibernate foreign key as primary key Robert Klemme <shortcutter@googlemail.com> - 2011-08-07 19:14 +0200
      Re: Hibernate foreign key as primary key Lionel <lionelv@none.com> - 2011-08-08 20:11 +1000
        Re: Hibernate foreign key as primary key Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-08-08 18:26 -0300
          Re: Hibernate foreign key as primary key Lionel <lionelv@none.com> - 2011-08-09 18:56 +1000
            Re: Hibernate foreign key as primary key Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-08-09 21:45 -0300
        Re: Hibernate foreign key as primary key Lew <lewbloch@gmail.com> - 2011-08-10 09:58 -0700

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