Re: shapes-ISSUE-168 (instance count): How to constrain number of instances of a class in a graph [SHACL - Core]

The way I understand it, when one uses scopeClass, the constraints apply
to each SHACL instance of a class individually. For example, each instance
of a Person can have only two parents. And a condition is tested against
each node individually.

This constraint, however, doesnąt apply to each instance individually. It
is about the number of all instances. This is quite different, so I
wouldnąt expect to use scopeClass.

Irene 






On 6/17/16, 1:10 PM, "Karen Coyle" <kcoyle@kcoyle.net> wrote:

>My preference overall would be to not use classes at all in validation;
>to have all operations on triples, and rdf:type would be simply a
>predicate like any other. (I believe that ShEx takes this approach.)
>However, if you encourage people to view the objects of rdf:type as
>classes, then you have to allow them to do so throughout,  otherwise it
>becomes difficult to explain "when is a class not a class?".
>
>With the solution in this proposal, we have what to the user is a class
>but it does not use scopeClass, and scopeNode binds to the subject of a
>triple, AFAI can determine. The below would not match the schema.org
>example.[1]
>
>kc
>[1] http://schema.org/FlightReservation
>
>
>On 6/13/16 5:04 AM, RDF Data Shapes Working Group Issue Tracker wrote:
>> shapes-ISSUE-168 (instance count): How to constrain number of instances
>>of a class in a graph [SHACL - Core]
>>
>> http://www.w3.org/2014/data-shapes/track/issues/168
>>
>> Raised by: Holger Knublauch
>> On product: SHACL - Core
>>
>> There was recent discussion about how to specify min/max numbers of
>>instances in a graph.  Off-list I had also received a question from
>>schema.org people about how to state that a graph/message must have
>>exactly one instance of schema:FlightReservation, possibly to ensure
>>that a graph has a starting point/root for validation.
>>
>> A possible syntax that would easily work with the current architecture
>>could be
>>
>> ex:MyShape
>>     a sh:Shape ;
>>     sh:scopeNode schema:FlightReservation ;
>>     sh:constraint [
>>         sh:minInstanceCount 1 ;
>>         sh:maxInstanceCount 1 ;
>>     ] .
>>
>>
>>
>>
>
>-- 
>Karen Coyle
>kcoyle@kcoyle.net http://kcoyle.net
>m: 1-510-435-8234
>skype: kcoylenet/+1-510-984-3600
>

Received on Friday, 17 June 2016 17:23:10 UTC