[sc34wg3] Type versus Class: settled yet?

[Robert Barta]

On Fri, Mar 21, 2003 at 06:42:32PM +0900, Mary Nishikawa wrote:
> Sorry for cross posting, but this terminology needs some discussion by WG3, 
> too.
> 
> *Bernard Vatant
> >>>BTW the use of type vs class should be made
> >>>consistent at least with SAM prose, but I assume "topic type" here means
> >>>"topic class")
> 
> Actually, I think we still need to come to grips with these. In Barcelona, 
> we decided to replace the term "class" with "type."
> 
> So now we should be using the terms topic type, subtype, and supertype. 
> While working on this draft, I found I really wanted to really use 
> "class"not "type." I don't think they are interchangable in all cases.

Mary,

Who cares? :-)

Seriously, the distinction class/type may be relevant for many areas
of data modelling, but I do not think it has any relevance for
SAM/../TMCL/TMQL.

Why? Because once we have modelled an "instanceOf" and the
"subclasses" relationship as associations with predefined association
types, they are treated as exactly this: normal, vanilla associations.

Whether the formal model is now graphs where TMs are broken down into
tiny graph fragments or whether the model is based on 'maplets'
(abstractions from the topic/assoc distinction) as I am having it
here; in all these models the above association types are not anything
specific, except that they may be predefined to allow simplified
reasoning for the usual

  if a is 'instanceOf' A and A 'subclasses' B then a is 'instanceOf' B

thing.

I agree, though, that we should try to have a consistent naming across
the standards, but this is more an editorial matter and not so much a
conceptual problem.

\rho