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Re: Comments and questions on SHACL

From: Thomas Francart <thomas.francart@sparna.fr>
Date: Wed, 4 Jan 2017 12:15:01 +0100
Message-ID: <CAPugn7UD-quhx3+QkWDGSosGnPc18KND+EiV3Gx=RQ68=tiiGg@mail.gmail.com>
To: Irene Polikoff <irene@topquadrant.com>
Cc: public-rdf-shapes@w3.org
2017-01-04 12:11 GMT+01:00 Thomas Francart <thomas.francart@sparna.fr>:

> A quick followup :
>
>
>> If this approach doesn’t work with your data and use cases, I think you
>> may have to create a shape for each property you need to implement such
>> constraint for. This could be done using something like:
>>
>> ex:TargetSubjectsOfProperty_p
>>
>>             a sh:Shape ;
>>
>>             sh:targetSubjectsOf ex:p ;
>>
>>               sh:property [
>>
>>                         sh:predicate rdf:type ;
>>
>>                         sh:class ex:C ;
>>
>>             ] .
>>
>> Or use sh:in instead of sh:class if members of multiple classes may have
>> values for this property.
>>
>
> Using sh:in for multiple classes is not possible as the semantic of sh:in
> is to check that the value of the property belongs to the list, not that
> the value is an instance of one of the members in the list.
>

Sorry, I am mixing things up, using sh:in on a PropertyConstraint on
rdf:type is of course possible to list multiple classes.


ex:TargetSubjectsOfProperty_p

            a sh:Shape ;

            sh:targetSubjectsOf ex:p ;

              sh:property [

                        sh:predicate rdf:type ;

                        sh:in ( ex:C1 ex:C2 ) ;

            ] .

Sorry ;-)
Thomas


> I think if the property can be expressed on multiple classes I need to use
> sh:or :
>
> ex:TargetSubjectsOfProperty_p
>
>             a sh:Shape ;
>
>             sh:targetSubjectsOf ex:p ;
>
>             sh:or [
>
>                [
>
>                sh:property [
>
>                         sh:predicate rdf:type ;
>
>                         sh:class ex:C1 ;
>                ]
>                ]
>
>                [
>
>                sh:property [
>
>                         sh:predicate rdf:type ;
>
>                         sh:class ex:C2 ;
>                ]
>                ]
>
>             ]
>  .
>
> Which is a little complex to write. Can any simplification be introduced
> in SHACL here ? (such as a "sh:classes" component that could take a list as
> a value, or having the ability to pass a list as the value of a "sh:class").
>
> Cheers
> Thomas
>
>
>
>
>> Note that unlike the closed shapes approach above, this will not use the
>> subclass hierarchy. So, if for example, you have a class ex:Party with
>> subclasses ex:Organization and ex:Person and you want any party to have
>> ex:homePage property, with closed shapes you could define the constraint at
>> the ex:Party level. And it will allow people and organizations (but not
>> members of a class that is not a sub of party) to have ex:homePage
>> property. If you use the target subjects approach, you would need to say:
>>
>> ex:TargetSubjectsOfProperty_homePage
>>
>>             a sh:Shape ;
>>
>>             sh:targetSubjectsOf ex:homePage ;
>>
>>               sh:property [
>>
>>                         sh:predicate rdf:type ;
>>
>>                         sh:in (ex:Party, ex:Person, ex:Organization) ;
>>
>>             ] .
>>
>>
>> I wonder if others can come up with some additional alternatives.
>>
>> Regards,
>>
>> Irene Polikoff
>>
>> On Jan 3, 2017, at 9:19 AM, Thomas Francart <thomas.francart@sparna.fr>
>> wrote:
>>
>> Hello
>>
>>    - In the example shapes graph at https://w3c.github.io/data-sha
>>    pes/shacl/#NodeKindConstraintComponent
>>    <https://w3c.github.io/data-shapes/shacl/#NodeKindConstraintComponent>,
>>    "sh:nodeKind ex:IRI ;" should be "sh:nodeKind sh:IRI ;"
>>    - In https://w3c.github.io/data-shapes/shacl/#nonValidation, I would
>>    find it useful to be able to express sh:order also on Shapes and not only
>>    PropertyConstraints, in order to display an ordered list of Shapes;
>>    - I have a doubt about the best way to express the equivalent of a
>>    "domain" contraint in SHACL, that is : "given a property :p, I want to make
>>    sure that all X that are subjects of :p have class C". Given that I have
>>    defined one Shape per Class in my ontology, can I express this without
>>    redefining an extra shape and keeping only one Shape per class ?
>>
>> Cheers
>> Thomas
>>
>> --
>>
>> *Thomas Francart* -* SPARNA*
>> Web de *données* | Architecture de l'*information* | Accès aux
>> *connaissances*
>> blog : blog.sparna.fr, site : sparna.fr, linkedin :
>> fr.linkedin.com/in/thomasfrancart
>> tel :  +33 (0)6.71.11.25.97 <+33%206%2071%2011%2025%2097>, skype :
>> francartthomas
>>
>>
>>
>
>
> --
>
> *Thomas Francart* -* SPARNA*
> Web de *données* | Architecture de l'*information* | Accès aux
> *connaissances*
> blog : blog.sparna.fr, site : sparna.fr, linkedin : fr.linkedin.com/in/
> thomasfrancart
> tel :  +33 (0)6.71.11.25.97 <+33%206%2071%2011%2025%2097>, skype :
> francartthomas
>



-- 

*Thomas Francart* -* SPARNA*
Web de *données* | Architecture de l'*information* | Accès aux
*connaissances*
blog : blog.sparna.fr, site : sparna.fr, linkedin :
fr.linkedin.com/in/thomasfrancart
tel :  +33 (0)6.71.11.25.97, skype : francartthomas
Received on Wednesday, 4 January 2017 11:16:12 UTC

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