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 Post subject: why seperate composite class
PostPosted: Sun Oct 22, 2006 4:47 pm 

Joined: Thu Apr 27, 2006 12:21 am
Posts: 4
I read some thing about how to mapping a composite key in the hibernate (against legacy db). It is recommended to seperate a composite key columns to a sperate class. Could you please provide what are advantages or disadvantages with this approach? -- or it is only way?


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PostPosted: Fri Oct 27, 2006 10:01 am 

Joined: Mon Nov 14, 2005 1:19 pm
Posts: 3
What I've found when mapping composite keys to a separate class, is that it's much easier to load the class. I'm using Spring, so with the primary key of any hibernate mapping, I can just pass it off to the fetchById() method, and it will return the object I want.

However, it makes querying with the criteria api a bit trickier. If I recall correctly (and please let me know if I'm wrong) you have to create a criteria on the main class and then create a subcriteria on the composite key class to add your restrictions.

Anymore, I do more querying than fetching by id, so I don't abstract the composite key elements into a seperate class. That's my preference.

Hope this helps.

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