Re: shapes-ISSUE-212 (Property constraints): Property constraints and focus node constraints [SHACL Spec]

I think this is not possible with the current class hierarchy but could
work if we adjust it

Currently sh:Constraint is the class of all constraints and focus node
constraints are instances of sh:Constraint
sh:PropertyConstraint is a subclass of sh:Constraint so disjointness would
not work
if we create another class for focus node constraint this could be possible

On Mon, Nov 28, 2016 at 12:40 PM, Holger Knublauch <holger@topquadrant.com>
wrote:

> We could just declare the constraint classes to be disjoint and achieve
> the same without revisiting the whole design. These are just artificial
> corner cases anyway - who would ever do this in practice?
>
> Sent from my iPad
>
> On 28 Nov. 2016, at 20:09, Dimitris Kontokostas <
> kontokostas@informatik.uni-leipzig.de> wrote:
>
> I think this problem stems from merging  node constraints with shapes.
> Before, focus node constraints were declared with sh:constraint and not
> directly into the shape and  were disjoint with property constraints so
> this problem could not occur.
>
> The proposed solution fixes this problem, but adding exceptions to
> definitions is not a good approach.
> I would prefer to reconsider our resolution
> https://www.w3.org/2016/07/28-shapes-minutes.html#resolution04
>
> On Thu, Nov 24, 2016 at 6:17 AM, Holger Knublauch <holger@topquadrant.com>
> wrote:
>
>> The email thread quoted below went back and forth, because the original
>> SHACL examples that Peter had given were syntactically incorrect. From what
>> I can see, the last unanswered email on this topic was
>>
>> https://lists.w3.org/Archives/Public/public-rdf-shapes/2016Nov/0012.html
>>
>> In the last sentence there, Peter claims that
>>
>> sh:pc2 is also a property constraint so the
>> constraint component is also checked with focus node ex:i1 and value node
>> ex:i2, which produces a validation report.  Therefore se:s2 produces a
>> validation report.
>>
>> However this case has been excluded through the addition of a sentence to
>> the Validation Definition in section 3:
>>
>> Note that validation against a shape processes the shape as a focus node
>> constraint
>> <#m_6642620271588933798_m_5129570904457041819_dfn-focus-node-constraints>
>>  only, even if the shape may have rdf:type triples or an expected type
>> <#m_6642620271588933798_m_5129570904457041819_dfn-expected-type> that
>> would also make them property constraints
>> <#m_6642620271588933798_m_5129570904457041819_dfn-property-constraints>.
>>
>> As a result of this, I believe we can close this issue as resolved.
>>
>> Holger
>>
>>
>>
>> On 23/11/2016 8:46, RDF Data Shapes Working Group Issue Tracker wrote:
>>
>> shapes-ISSUE-212 (Property constraints): Property constraints and focus node constraints [SHACL Spec]
>> http://www.w3.org/2014/data-shapes/track/issues/212
>>
>> Raised by: Karen Coyle
>> On product: SHACL Spec
>>
>> Peter's email: https://lists.w3.org/Archives/Public/public-rdf-shapes/2016Nov/0005.html
>>
>> Data Graph D:
>>
>> ex:i1 rdf:type ex:c ;
>>  ex:p1 ex:i2 .
>>
>> 1/ property constraints and focus node constraints
>>
>> Shapes Graph S1:
>>
>> se:s1 rdf:type sh:Shape ;
>>   sh:targetClass ex:c ;
>>   sh:property [ sh:predicate ex:p2 ;
>>                 sh:property se:s2 ] ;
>>   sh:shape se:s2 .
>> se:s2 sh:predicate ex:p1 ;
>>   sh:class ex:c .
>>
>> Validating D against S1 produces the following validation report
>>
>> [ rdf:type sh:ValidationResult ;
>>   sh:severity sh:Violation ;
>>   sh:focusNode ex:i1 ;
>>   sh:sourceConstraintComponent sh:ShapeConstraintComponent ;
>>   sh:sourceShape se:s1 ] .
>>
>> It is actually a tiny bit unclear what makes a property constraint.  There
>> is wording that values of sh:property have sh:PropertyConstraint as expected
>> type, but there is no actual explicit connection between nodes with expected
>> type sh:PropertyConstraint.  However, se:s2 is definitely a property
>> constraint as it is the value of sh:property in a shape.
>>
>>
>>
>>
>>
>>
>
>
> --
> Dimitris Kontokostas
> Department of Computer Science, University of Leipzig & DBpedia
> Association
> Projects: http://dbpedia.org, http://rdfunit.aksw.org,
> http://aligned-project.eu
> Homepage: http://aksw.org/DimitrisKontokostas
> Research Group: AKSW/KILT http://aksw.org/Groups/KILT
>
>


-- 
Dimitris Kontokostas
Department of Computer Science, University of Leipzig & DBpedia Association
Projects: http://dbpedia.org, http://rdfunit.aksw.org,
http://aligned-project.eu
Homepage: http://aksw.org/DimitrisKontokostas
Research Group: AKSW/KILT http://aksw.org/Groups/KILT