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From "Albert L. Sapp" <as...@uiuc.edu>
Subject Re: n+1 relation table
Date Wed, 18 Jan 2006 15:01:35 GMT
Gregg D Bolinger wrote:

> I've search the archives and have found a few similar issues but 
> nothing conclusive to what I am doing.  I can only assume no one else 
> has this problem because they know what they are doing and I don't 
> (most likely) or no one is simply doing things the way I am doing 
> them.  At any rate...
>
> I have a table called items and this table contains a fk to a type_id 
> from a table called type.  I then have a 3rd table called items_types 
> which contains an item_id and a type_id.
>
> Got that?  So in my Item class I will need to get a List<Type> of 
> types.  I know how to do the n+1 solutions but  by adding in this 
> third table I am at a loss on how to map it.  If anyone could point me 
> into the right direction, I would appreciate it.  A link to an 
> archived question, a page in the user docs, etc. 
>
> Thanks a bunch.
>
> Gregg

Gregg,

Is there a reason why you need the type_id as a foreign key in the item 
table?  You have a relationship defined between and iten and its type in 
the third table.  If you are worried about uniqueness, simply define the 
combinations in the third table as needing to be unique.  We do a 
similar thing in many of the modules in our application.  It requires 
additional reads to get all the information together and this may not be 
the best design, but it works for us.

This probably did not directly answer your question, just curious as to 
why you had that foreign key defined.

Respects,

Al


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