Sergey,

Sorry. I haven¹t been very clear. Let me try again here.

The changes that we¹ve made in the Context Data Model 1.1, and implemented
in IdAS mean that we now have a data model that can represent RDF graphs as
CDM entities, simple (literal) attributes and complex (entity-valued)
attributes in a very natural way. This opens up the possibility of CDM/IdAS
contexts containing not just ³instance² data (e.g. the (entity attribute
attribute-value) statement (paul eyeColor green)) but also statements like
(paul rdf:type :Person) and, more to the point of what we are discussing
here, statements about the Person class itself. And of course of this is
exactly how things are done in in the world of RDF.

I¹m proposing that we model in CDM classes of entities and kinds of
attributes using entities and attributes. We would use the URI rdf:type to
link an instance entity to its class entity(ies). And we would use various
RDF vocabularies to describe these classes of entities and attributes. All
that remains for us (e.g. me) to do is to document on the CDM page on the
Higgins wiki exactly which vocabularies we are using, and which parts of
them. The obvious choice is to use the RDFS vocabulary. Some of OWL is may
be useful. I find that parts of the SPIN (see http://spinrdf.org) vocabulary
may also be extremely useful. SPIN introduces ways to model closed-world,
OOP concepts of classes and attributes that I think Context CP developers
will find familiar and useful, which still allowing open world models like
native RDF.

With this approach no further changes are required to IdAS, and we don¹t
need the current Model interfaces. What does change with this approach is
that if a context developer wants to express the ³class² aspects of the
entity and attribute instances in their context data set, they would need to
populate their context (or some context) with yet more entities that
describe classes of entities and attributes (e.g. as owl:Classes,
owl:DatatypeProperties and owl:ObjectProperties). If they do this, the the
existing Higgins IdAS 1.1 API can be used to inspect and navigate these
³class² entities.

--Paul




On 10/20/09 11:07 AM, "Sergey Lyakhov" <[email protected]> wrote:

> Paul,
>  
>>> >> Actually, Model API could correctly treat a polymorphism in a schema. Are
>>> you going to replace it with a model proposed by
>>> >> Jim a year ago (I and Valery think it is not convenient to use it) or
>>> plain just to use owl schema instead of Model API?
> 
>> > ## I have yet another idea up my sleeve. Valery probably won¹t like it
>> either, but we¹ll see. I¹ll let you know within 1 week.
> When I wrote  "...replaces IModel interfaces with something you were going to
> propose" here http://dev.eclipse.org/mhonarc/lists/higgins-dev/msg06101.html
> <http://dev.eclipse.org/mhonarc/lists/higgins-dev/msg06101.html>   , I
> supposed you have a new idea to replace IModel interfaces with something.  It
> looks I misunderstood your sentence.

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