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

From: Holger Knublauch <holger@topquadrant.com>
Date: Thu, 24 Nov 2016 14:17:42 +1000
To: public-data-shapes-wg@w3.org
Message-ID: <287aaf4e-e8e9-222f-df30-ce6bd0eac716@topquadrant.com>
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 afocus node 
constraint <#dfn-focus-node-constraints>only, even if the shape may 
have|rdf:type|triples or anexpected type <#dfn-expected-type>that would 
also make themproperty constraints <#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.
>
>
>
Received on Thursday, 24 November 2016 04:18:20 UTC

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