I've often wondered about this as well, and figured I was missing something. But for this use case, two separate vocabularies would capture the same data, and it would be easier for the end user to comprehend: Type of Fish -shark -salmon -eel -cod -trout -carp Habitat -ocean -lakes -rivers -marsh -brackish I think this is one of those cases where we should ask a librarian -- when it comes to explaining uses for taxonomy/categorization, I have found that librarians can explain use cases I have never imagined. Cheers, Bill Gerhard Killesreiter wrote:
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Robert Douglass schrieb:
In my opinion, any time multiple parents are used it is a mistake in the data model. For example, if you have regional offices and each office has a sale, customer and advertising contact person, you might be tempted to model the data like this:
How about:
Fish living in:
- - salt water . shark . salmon . eel . cod
- - fresh water . trout . salmon . eel . carp
Cheers, Gerhard -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux)
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-- Bill Fitzgerald http://www.funnymonkey.com Tools for Teachers 503.897.7160