Re: shapes-ISSUE-86 (dimitris): Associating shapes with ontologies or vocabularies [SHACL Spec]

On 10/2/2015 18:51, Dimitris Kontokostas wrote:
>
>
> On Thu, Oct 1, 2015 at 11:49 PM, Holger Knublauch 
> <holger@topquadrant.com <mailto:holger@topquadrant.com>> wrote:
>
>     On 10/1/15 5:04 PM, Dimitris Kontokostas wrote:
>>     Now that it is more clear I would like to propose my resolution
>>     of issue-86.
>>
>>     I suggest the spec mentions something in the lines of the
>>     following sentence
>>     ontology or vocabulary designers that want to publish SHACL
>>     constraints along with their schemas are encouraged (or SHOULD)
>>     either define the associated shapes in the same document with the
>>     schema or link to them through the sh:shapesGraph property.
>
>     sh:shapesGraph would not have the right effect. It would basically
>     only say that the ontology (e.g. definition of skos:Concept)
>     itself would have to follow the shape definitions. I believe it
>     should be owl:imports instead.
>
>
> owl:imports and inline declaration have the exact same effect. the 
> problem with those is that if a user imports an ontology in the data 
> graph, she automatically loads the shapes as well which might not be 
> what the user expects / wants.

I believe for a large number of use cases, esp for people beginning with 
SHACL, we should promote the simplest possible design in which - like 
with OWL - instance, class, property (and shapes) all live in the same 
logical graph and owl:imports are used. This avoids many issues and 
lowers frustration and negative press like "this is over-engineered 
complicating stuff, let's not bother with SHACL". Many people will 
already wonder why we came up with this whole parallel universe of 
"shapes" anyway.

I think what we need is a careful analysis of less than a handful of 
set-ups that we can reasonably support, and put best practice recipes 
for those set-ups into our documentation. So I retract my previous 
comments, and now believe that we indeed need to do something here with 
this ticket.

Holger


>
> I agree that sh:shapesGraph does not have the exact semantics in this 
> case but when the ontology is loaded in the data graph, sh:shapesGraph 
> gets proper semantics again.
> We can redefine the semantics of sh:shapesGraph or introduce a new 
> property for this
>
>     Overall, I don't think we need to specify or recommend anything
>     here. There will be different design patterns emerging, and we
>     cannot anticipate yet which variation people will prefer, how
>     SHACL will relate to OWL etc.
>
>
> If we do not recommend anything we are forcing people to write shapes 
> inline or use owl:imports which might have an undesired effect.
> I am ok with that, although I would prefer to have an alternative.
>
> Dimtiris
>
>
>
>     Holger
>
>
>
>>
>>     This is independent of Peter's suggestion and if the WG thinks
>>     that Peter's suggestion should also exist in the spec I would
>>     vote +1 on this as well.
>>
>>     Dimitris
>>
>>     On Thu, Oct 1, 2015 at 8:43 AM, Dimitris Kontokostas
>>     <kontokostas@informatik.uni-leipzig.de
>>     <mailto:kontokostas@informatik.uni-leipzig.de>> wrote:
>>
>>
>>
>>         On Thu, Oct 1, 2015 at 5:35 AM, Peter F. Patel-Schneider
>>         <pfpschneider@gmail.com <mailto:pfpschneider@gmail.com>> wrote:
>>
>>             I do not see that SHACL needs any connection between a
>>             shapes graph and an
>>             ontology definition.
>>
>>             For purposes of designing a collection of shapes, having
>>             access to an ontology
>>             that provides axioms about the classes in a collection of
>>             shapes is handy.
>>             However, validating SHACL shapes or documents against a
>>             data graph or node in
>>             a data graph does not need any link going from the shapes
>>             graph to an ontology
>>             graph.   A SHACL validation engine does need to have
>>             access to ontology axioms
>>             to determine whether a node in the data graph is a SHACL
>>             instance of a class,
>>             but this is best done by including a graph with the
>>             required ontology axioms
>>             into the data graph.
>>
>>             I therefore vote 0 for a) and -1 for the other options.
>>
>>
>>         Peter,
>>
>>         I also do not think that shacl needs a link to an
>>         ontology/vocabulary.
>>         The issue subject is indeed not clear but the intent was
>>         about the reverse relation: ontology/vocabulary to shacl
>>
>>         e.g. skos could define their additional constraints [1] in
>>         shacl and my issue was about how could e.g. skos publish
>>         these constraints
>>
>>         Dimitris
>>
>>         [1] http://www.w3.org/TR/2009/REC-skos-reference-20090818/#L2422
>>
>>
>>             I would vote +1 for a proposal like:
>>
>>             PROPOSED: The SHACL spec states that there is no need for
>>             a link from a SHACL
>>             shapes graph to an ontology graph and does not define
>>             such a link.  The SHACL
>>             spec further states that there is nothing in SHACL to
>>             prevent a SHACL shapes
>>             graph from including ontology axioms or importing
>>             ontology axioms, but that
>>             such inclusion or importation has no effect on
>>             determining whether a node in a
>>             data graph is a SHACL instance of a class.  The SHACL
>>             spec states that
>>             ontology axioms that affect SHACL are either part of the
>>             data graph or
>>             included from the data graph.  The SHACL spec mentions
>>             that SHACL shape
>>             graphs are often best developed in conjunction with a set
>>             of ontology axioms
>>             and that tools for the development of SHACL shapes may
>>             want to provide
>>             mechanisms for viewing axioms from a separate ontology.
>>
>>             This proposal clearly makes the required distinction
>>             between what is required
>>             for SHACL validation and thus should be part of the SHACL
>>             language, and what
>>             is useful for SHACL development and thus should not be
>>             part of the SHACL language.
>>
>>
>>             peter
>>
>>
>>             On 09/10/2015 01:09 AM, RDF Data Shapes Working Group
>>             Issue Tracker wrote:
>>             > shapes-ISSUE-86 (dimitris): Associating shapes with
>>             ontologies or vocabularies [SHACL Spec]
>>             >
>>             > http://www.w3.org/2014/data-shapes/track/issues/86
>>             >
>>             > Raised by: Dimitris Kontokostas
>>             > On product: SHACL Spec
>>             >
>>             > Related to ISSUE-44, this is issue is about ways to
>>             associate an ontology or vocabulary to a set of shapes.
>>             >
>>             > Possible ways to resolve it
>>             > a) SHACL spec says nothing about associating
>>             ontologies/vocabularies with shapes
>>             > b) SHACL spec suggests the use of owl:imports
>>             > c) SHACL spec suggests the use of sh:shapesGraph
>>             > d) SHACL spec suggests shapes are defined in the same
>>             file with the ontology/vocabulary
>>             > e) SHACL spec suggests a combination of (d) with (b) or (c)
>>             >
>>             >
>>             >
>>
>>
>>
>>
>>         -- 
>>         Dimitris Kontokostas
>>         Department of Computer Science, University of Leipzig &
>>         DBpedia Association
>>         Projects: http://dbpedia.org,
>>         http://http://aligned-project.eu, http://rdfunit.aksw.org
>>         Homepage:http://aksw.org/DimitrisKontokostas
>>         Research Group: http://aksw.org
>>
>>
>>
>>
>>     -- 
>>     Dimitris Kontokostas
>>     Department of Computer Science, University of Leipzig & DBpedia
>>     Association
>>     Projects: http://dbpedia.org, http://http://aligned-project.eu,
>>     http://rdfunit.aksw.org
>>     Homepage:http://aksw.org/DimitrisKontokostas
>>     Research Group: http://aksw.org
>>
>
>
>
>
> -- 
> Dimitris Kontokostas
> Department of Computer Science, University of Leipzig & DBpedia 
> Association
> Projects: http://dbpedia.org, http://http://aligned-project.eu, 
> http://rdfunit.aksw.org
> Homepage:http://aksw.org/DimitrisKontokostas
> Research Group: http://aksw.org
>

Received on Monday, 5 October 2015 23:40:32 UTC