[oslc-core] Rethinking link labels without reified statements
Steve K Speicher
sspeiche at us.ibm.com
Tue Jun 26 14:28:53 EDT 2012
Based on review on the mailing list and at last Core WG call, I consider
this to be closed with no changes. Just summarizing with the following
observation:
1. We are not using anything that is really being scoped out of the new
work by W3C RDF WG, for example we only use rdf:* class/predicates and
blank nodes.
2. There really isn't an acceptable alternative. Alternatives require us
to reach a similar conclusion to what is defined using reification.
I will continue to track RDF WG activity with reification with this usage
in mind.
Thanks,
Steve Speicher | IBM Rational Software | (919) 254-0645
> From: Steve K Speicher/Raleigh/IBM at IBMUS
> To: oslc-core at open-services.net,
> Date: 06/12/2012 03:11 PM
> Subject: [oslc-core] Rethinking link labels without reified statements
> Sent by: oslc-core-bounces at open-services.net
>
> In looking at what is on the roadmap for the W3C RDF Working Group in
> considering deprecating reified statements [1] I took the action to
> explore the way we currently do things like "link labels" [2] using the
> recommended alternative of named graphs[3]. I'm sending this note out
to
> see if anyone else has any interesting insight on how this can be
> accomplished. I plan to send a note to the RDF WG as well.
>
> To be honest, I struggle to find a clean way to do this with named
graphs.
> Added to some of the challenges is how to define a simple PATCH format
> that can be used to patch these reified statements.
>
> Take for example this simple change request:
> @prefix ex: <http://example.com/bugtracker> .
> @prefix oslc: <http://open-services.net/ns/core#> .
> @prefix oslc_cm: <http://open-services.net/ns/cm#> .
> @prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
> @prefix dcterms: <http://purl.org/dc/terms/> .
>
> <http://example.com/bugs/2314>
> a oslc_cm:ChangeRequest ;
> oslc_cm:relatedChangeRequest <http://myserver/mycmapp/bugs/1235> ,
> <http://remoteserver/mycmapp/defects/abc123> .
>
> _:b1
> a rdf:Statement;
> rdf:subject <http://example.com/bugs/2314>;
> rdf:predicate oslc_cm:relatedChangeRequest;
> rdf:object <http://myserver/mycmapp/bugs/1235>;
> dcterms:title "My special link title".
>
> So if I want to NOT use reified statements I'd have to model this
> relationship a bit differently. One idea would be to use a named graph
> for the link statements.
> The questions that need to be answered with this approach are:
>
> 1. Simply how to form that graph and/or how to relate the graph with the
> right "relationship" triple?
>
> In thinking through this, it feels like I'm inventing reification and
> doesn't seem like the desired outcome. Let's try to force it for a
moment
> and say we can "compute" the graph name based on the relationship
triple.
> So for my example above, we have something horrible like (not encoding):
> Graph name = <
http://example.com/bugs/2314|http://open-services.net/ns/cm#
> relatedChangeRequest|http://myserver/mycmapp/bugs/1235>
>
> 2. What is the subject of the triples within this new named graph?
> The subject and object of the relationship triple don't appear to be the
> right choice. Though, since we have this special private graph, perhaps
> we can just use the object to pick one since we shouldn't have any
> conflicts.
>
> So the example becomes:
>
> @prefix ex: <http://example.com/bugtracker> .
> @prefix oslc: <http://open-services.net/ns/core#> .
> @prefix oslc_cm: <http://open-services.net/ns/cm#> .
> @prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
> @prefix dcterms: <http://purl.org/dc/terms/> .
>
> <http://example.com/bugs/2314>
> a oslc_cm:ChangeRequest ;
> oslc_cm:relatedChangeRequest <http://myserver/mycmapp/bugs/1235> ,
> <http://remoteserver/mycmapp/defects/abc123> .
>
> :<http://example.com/bugs/2314|http://open-services.net/ns/cm#
> relatedChangeRequest|http://myserver/mycmapp/bugs/1235> = {
> <http://myserver/mycmapp/bugs/1235> dcterms:title "My special link
> title". # This is a lie, not right subject
> }
>
> This seems like a complete non-obvious abuse of this. Hopefully
someone
> sees a more clear way to leverage named graphs and why I'm taking this
> discussion to the mailing list. If not, we can provide this feedback to
> RDF WG and see if they have a proper solution or will justify keeping
> reification or some subset.
>
> [1] - http://www.w3.org/2011/rdf-wg/track/issues/25 ,
> http://open-services.net/pipermail/oslc-core_open-services.net/2012-
> February/001229.html
> [2] -
>
http://open-services.net/bin/view/Main/OslcCoreSpecAppendixLinks#2_Anchor
> [3] -
> http://www.w3.org/TR/2012/WD-rdf11-concepts-20120605/#section-dataset
>
> Thanks,
> Steve Speicher | IBM Rational Software | (919) 254-0645
>
>
> _______________________________________________
> Oslc-Core mailing list
> Oslc-Core at open-services.net
> http://open-services.net/mailman/listinfo/oslc-core_open-services.net
>
More information about the Oslc-Core
mailing list