[topicmapmail] Scoping: Associations or roles?

[Jan Algermissen]

"Thomas B. Passin" wrote:
> 
> Steve Pepper wrote:

> > 1) We couldn't come up with a convincing use case for the
> >    use of multiple scopes within the same association.
> >
> 
> I can.  Say you have an association representing the relationship of
> players to a sports team.  The athletes play roles in the association.
> Not only to they come and go at various times, but from time to time one
> player will assume the additional role of, say, team captain.  Thus the
> "team captain" role would be played by different athletes at different
> times.
> 
> Without the ability to apply scopes to the roles, we are forced to some
> kind of roundabout construction, such as relating a time history to the
> team, even though what is really desired is to relate the players, not a
> history.

Thomas--

an association represents a particular relationship and the subject
(the is-ness, the nature) of an association is completely determined 
by the sum of all role playings. If the role playings change, the
relationship changes and thus you end up with a different association.
Scoping inside an association really makes no sense.

What you describe has to be modeled with individual associations between
the team and the individual players.

I find the team/players metaphor particulary difficult, because it is
easy to confuse team-player (team member) with role-player. These are
concepts at totally different levels.

But I am curious: you seem to think that team-membership cannot/should not
be modeled as individual associations, why?

Jan

-- 
Jan Algermissen                           http://www.topicmapping.com
Consultant & Programmer	                  http://www.gooseworks.org