Re: shapes-ISSUE-40 (Property Cardinality): sh:min/max constrains properties, not values

On 4/6/15 7:00 PM, Holger Knublauch wrote:
> I have attempted to clarify this via
>
> https://github.com/w3c/data-shapes/commit/1ffa8cd3225d2cc340ae3883abd5411913d7a7d4
>
>
> Please let me know if this helps. I had started to use the term "value"
> because I thought that "object" is less clear to newcomers who are not
> too familiar with RDF technology. Yet for a formal spec, using the term
> "object" may indeed be less objectionable.

Sorry, Holger, trading "object" for "value" doesn't help -- my confusion 
was something else.

What exactly is being constrained in:

"The properties sh:minCount and sh:maxCount restrict the number of 
objects in triples with the focus node as the subject and the given 
property as the predicate"

I think what you are saying is that you are restricting the number of 
times a particular predicate can appear in the focus node. Right? 
Because this is listed as a property constraint. Where do the objects 
come into that if this is a constraint on the propert(y/ies)? It's the 
"objects in triples" that throws me off -- number of objects in a triple 
is 1, right? So clearly I'm not reading this with the meaning you intend 
to convey.

kc

>
> Holger
>
>
> On 4/6/2015 2:08, RDF Data Shapes Working Group Issue Tracker wrote:
>> shapes-ISSUE-40 (Property Cardinality): sh:min/max constrains
>> properties, not values
>>
>> http://www.w3.org/2014/data-shapes/track/issues/40
>>
>> Raised by: Karen Coyle
>> On product:
>>
>> The spec at https://w3c.github.io/data-shapes/shacl/ currently reads:
>>
>> "The properties sh:minCount and sh:maxCount restrict the number of
>> values of the given property at the focus node."
>>
>> It should read:
>> "The properties sh:minCount and sh:maxCount restrict the cardinality
>> of properties of the focus node."
>>
>> The cardinality of the value of a triple is always min=1 max=1. It is
>> the cardinality of the properties in the node that can be constrained,
>> e.g.
>>
>> sh:property [
>>         sh:predicate foaf:name ;
>>         sh:minCount 1 ;
>>         sh:maxCount 1 .
>>
>>
>>
>>
>>
>
>
>

-- 
Karen Coyle
kcoyle@kcoyle.net http://kcoyle.net
m: 1-510-435-8234
skype: kcoylenet/+1-510-984-3600

Received on Tuesday, 7 April 2015 03:20:32 UTC