Re: [topicmaps-comment] mapping topic maps on a relation database

[Steve Pepper <pepper@ontopia.net>]

At 09:32 17/04/02 -0400, Thomas B. Passin wrote:
>[franck legoux]
> >
> > Does someone has a model to map "topic maps" on a
> > relational database ?
>
>...
>
>2) How to handle multiple role-playing topics with the same role

Unless your application needs to be able to preserve the exact syntactic 
form of the input topic map (in which case, I wish you luck :-), you can 
simply exploit the rule in Annex F of XTM 1.0 relating to "Equivalence of 
Multiple <member>s of the Same Role" (F.3.3) which states that:

"An association containing multiple members, M1 and M2 of the same role R 
may be equivalently defined by an association containing a single member M3 
of role R whose set of players is the union of the sets of players of role 
R in members M1 and M2."

If your input document contains a <member> element containing multiple 
role-playing topics, you simply treat it as multiple <member> elements 
(with the same <roleSpec>), each containing a single role-playing topic.

Steve

--
Steve Pepper, Chief Executive Officer <pepper@ontopia.net>
Convenor, ISO/IEC JTC1/SC34/WG3  Editor, XTM (XML Topic Maps)
Ontopia AS, Waldemar Thranes gt. 98, N-0175 Oslo, Norway.
http://www.ontopia.net/ phone: +47-23233080 GSM: +47-90827246