Re: [OWL] annotations and meta-modelling in OWL 1.1

On 9 Jan 2006, at 03:37, Bijan Parsia wrote:

> On Jan 8, 2006, at 6:10 PM, Enrico Franconi wrote:
>
>> In database systems, pleople use aggregation functions to  
>> characterise the values of properties of sets of tuples: see SQL!  
>> That is, you can have a property of a set of tuples defined in  
>> some way (e.g., average of the values of a property of all  
>> elements of the set of all tuples having some other property, etc).
>
> Yep. But are these people wanting to use OWL for anything? UML  
> maybe, though I've not seen *UMLers* step up and request this  
> stuff. You're experience might vary. If there were a clear UML  
> application (ICOM? :)) that we were targeting as a kind of killer  
> app for owl, I would find that example more compelling. But then  
> I'd want a plan for sweeping the UML folks off their feet.

Aggregation is ubiquitous in databases and SQL. It is not present in  
standard conceptual modelling languages (e.g., EntityRelationship E/R  
data model) for historical reasons (they came before SQL). It has a  
minor presence in UML (the association with a diamond at one end) -  
but UML was not conceived as a database conceptual modelling  
language. There is *plenty* of proposals for extension of the E/R  
data model (and for UML) to model conceptually aggregations, and all  
the conceptual modelling tools I know about have some (non-standard)  
hook to model aggregation. DL people (me, Uli, et al) did study  
extensions of DLs with aggregations, and I came up with an extension  
of E/R (and UML) which (a) is implemented in ICOM (the DL based  
conceptual modelling tool), and (b) deserved a chapter in a  
Datawarehouse design book :-).
I also mentioned aggregation since I'd say it is the typical use case  
for meta-modelling.
If OWL starts to catch up to model databases and more generally  
information integration (which we really hope!), then aggregation  
will become ubiquitous as well. I wonder whether people in the SWBP  
WG came up with such a modelling requisite.

> Or more simply, I don't know what the dominant set of users for  
> robust metamodeling are thus have a hard time assessing the utility  
> of standardizing various proposals. Annotations (with full punning)  
> are ubiquitous and highly desired and (mostly) easy. So I find them  
> reasonable for 1.1.

The reason why they are ubiquitous in OWL is because they are already  
as a partial feature in OWL.

cheers
--e.