Re: rdfdatashapestracker-ISSUE-3 (Shape association): How is a shape associated with a graph?

If I understand the ticket's purpose correctly, then there are two 
dimensions

a) how to store, reference and share constraint definitions in graphs 
(Peter addressed that)
b) how to instruct an engine so that it knows which checks to perform

On b) I believe there is a wide agreement that associating "shapes" with 
classes makes a lot of sense, and I believe all proposed mechanisms have 
some vocabulary for that purpose (in SPIN and OWL this is simply relying 
on the rdf:type arcs). At the same time, there are use cases where this 
association with classes is not the only mechanism, and some resources 
need to be checked against additional patterns in specific contexts. In 
Resource Shapes 2.0 this is done (among others) via oslc:valueShape, and 
it sounds straight-forward to define similar properties that can be 
submitted as part of a constraint checking request. Resource Shapes 2.0 
seems to have oslc:instanceShape and oslc:resourceShape for that 
purpose. I believe oslc:instanceShape is similar to rdf:type. 
oslc:resourceShape seems rather specific to the web service 
architecture, and I am not sure how far the WG will reach in this 
regard. I would argue the latter could be an OSLC specific extension 
because it relies on concepts outside of our focus.

At this stage I am not sure what is missing to resolve this ticket. The 
ticket is about collecting all ways a shape can be associated with a 
graph. Peter has enumerated some. I have written that the rdf:type 
triples can be used. Who can elaborate on the other mechanisms employed 
by ShEx and Resource Shapes, and clarify which ones are proposed to be 
handled by the WG?

Thanks,
Holger


On 12/3/2014 5:58, Peter F. Patel-Schneider wrote:
> On 11/18/2014 09:17 AM, RDF Data Shapes Working Group Issue Tracker 
> wrote:
>> rdfdatashapestracker-ISSUE-3 (Shape association): How is a shape 
>> associated with a graph?
>>
>> http://www.w3.org/2014/data-shapes/track/issues/3
>>
>> Raised by: Arnaud Le Hors
>> On product:
>>
>> There has been quite a bit of discussion about how a shape is 
>> associated with an instance graph. Some technologies rely on a type 
>> but this isn't accepted by all as sufficient to address all use 
>> cases. So, what are the ways a shape can be associated with a graph?
>
>
> As far as I can see there are only a few potential mechanisms for 
> associating some constraints with an RDF graph.  (This is separate 
> from determining which part of the RDF graph the constraint acts on, 
> by the way.)
>
> 1/ The constraint could be in the graph itself.
>
> 2/ There could be an explicit connection between the graph and a 
> source for the constraint.  This would work something like 
> owl:imports, but the source would not have to be an ontology 
> document.  The connection could also be indirect, e.g., the graph 
> owl:imports an ontology document which is itself explicitly connected 
> to a constraint document.
>
> 3/ There could be an implicit connection between the graph and a 
> source for the constraint.  This could be something like "follow your 
> nose", i.e., the graph has a node whose IRI can be turned into a URL 
> that points at a source for the constraint.  This connection could 
> also be indirect.
>
> 4/ The constraint validation mechanism could take multiple arguments, 
> one of which is an RDF graph and another of which contains 
> constraints.  In this mechanism, as opposed to the other three, there 
> is no way of navigating from the RDF graph to the constraint.
>
>
> Some proposals naturally or easily work with several of the above 
> mechanisms.
>
>
> peter
>
>

Received on Wednesday, 3 December 2014 00:56:25 UTC