RE: [SE] Suggestion of new note

See inline comments.

============================================
Mike Uschold
Tel: 425 865-3605              Fax: 425 865-2965
============================================



>  -----Original Message-----
>  From: ewallace@cme.nist.gov [mailto:ewallace@cme.nist.gov] 
>  Sent: Tuesday, October 04, 2005 1:48 PM
>  To: holgi@stanford.edu; Uschold, Michael F
>  Cc: public-swbp-wg@w3.org
>  Subject: RE: [SE] Suggestion of new note
>  
>  
>  
>  Michael Uschold wrote:
>  >Here are my latest slides on the difference between 
>  object-oriented and 
>  >OWL.
>  
>  Some comments
>  
>  Regarding slide 2:
>  
>   Object models (e.g. UML 1.x or precursors) support multiple 
>  inheritence. Even 
>   when disjoint subtype coverings are specified, an instance 
>  can have multiple 
>   types (it's instantiated type and each supertype of that type).

I guess there may be a distinction between UML and object-oriented
software development in general. My understanding is that traditional
object models:
* only allow strict taxonomy, a class cannot have more than one direct
superclass
* an instance can only be a direct member of one class, it is an
indirect member of all that class's superclasses, by inheritance.

It may be that UML 1.x goes beyond this limitation. Is this correct?
  
>  Regarding slide 3:
>  
>   Not sure what you are identifying with term "property" in 
>  the OO context.  This 
>   is because attributes and relations (uml:Association) are 
>  treated differently in OO.  The statement "Properties 
>  attached to single class" isn't quite right for OO attributes 
>   or relations.  Perhaps this would be better written 
>  "Attributes are defined locally  to a class".  Thus 
>  attributes with the same name in different classes do not 
>   denote the same attribute.

OK, thanks, I had not realized that.
  
>   Associations (relations) are defined with respect to 
>  particular classes at their 
>   AssociationEnds.  Thus Associations are attached to one or 
>  (usually) more classes.  

This means an association is very much like an OWL property (relation).
Is it true that an association is just like an OWL property, in that it
stands alone separate from any particular class, and the association
ends are exactly analogous to domain and range constraints? Are there
any important differences? What are they?

Also due to ignorance, I was being sloppy, using 'property' and
'attribute' very generically.
Thanks for tightening this up a bit.

>  -Evan
>  
>  
>  
>

Received on Wednesday, 5 October 2005 02:22:16 UTC