not sure I entirely understand your question...
In oracle I would do something like this using hierarchical queries -
Category[
category_id (PK)
]
Subcategory[
category_id (FK - Category)
subcategory_id (FK - Category)
]
Thing[
thing_id (PK)
]
ThingCategory[
thing_id (FK - Category)
category_id (FK - Category)
]
select thing_id from ThingCategery where category_id in (
select "Animal" from dual UNION
select subcategory_id from Subcategory
start with category_id = "Animal"
connect by category_id = prior subcategory_id
)
Dont know if you could do it with CMP, but with BMP it might work. As long
as you only want 2 EJB types. Now if you want different EJB types for
Animal Things, Dog Things, Rottweiler Things, etc, that would be more
difficult. Although even that would be doable with BMP. I guess Im curious
as to exactly which issues you are concerned about. Or am I
misunderstanding your questions?
-----Original Message-----
From: Peter Routtier-Wone [mailto:[EMAIL PROTECTED]]
Sent: Friday, February 16, 2001 4:59 PM
To: JBoss-User
Subject: Re: [jBoss-User] Recursive data structures
> Did that answer part of your question ?
Well, Tobias, you raise more questions than you answer. But they are good
questions, and you are the first (other) person I've ever met who appears to
completely understand the problem. That in itself is encouraging. If you
wish I shall post the (preliminary) source for the helper object I put
together. It would work but for a problem with comparison of references
instead of values.
EJB at large tackles infrastructural problems. This is one such. If you
could find the time to look into this issue with me, I believe it to be of
profound significance. I won't rant about how much this sort of general
solution improves the normalisation of underlying schemata - you plainly
understand that. But I will say that this is highly desirable. I want to use
it for charts of accounts, which are taxonomies, and I'm quite sure the
scientific world can use such a thing.
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