Nesting queries within active record

[eluser]Sumon[/eluser]
Tree concept seems to me all about category or parent category name. But what about the item description while i am using binary tree. moreover, category and item tables doesn't contain same properties. so as a result how to get

Code:

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instead of

Code:

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using a query in the model without loop or apply logic in view?

[quote author="E.T.Cook" date="1223102492"]
Is there any way to do it without looping each query separately, and manually propagating an array? On the rails version of active record, I believe you use :through, but I can't seem to find anything like that here.
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@E.T.Cook: is it really in rails active record? if yes then is rail process (in model or somewhere builtin) the data by looping and applying logic and return desired value. is it?