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Re: ISSUE-110: Can we close this?

From: Karen Coyle <kcoyle@kcoyle.net>
Date: Mon, 9 May 2016 12:23:56 -0700
To: public-data-shapes-wg@w3.org
Message-ID: <5730E3CC.1050004@kcoyle.net>
The problem that I have with this is "apply":

"sh:PropertyConstraint is the class of all property constraints. Property
constraints apply on the value of a property on the focus node. "

First, the class here doesn't seem to be used within the shapes graph - 
as I've mentioned elsewhere, in many cases the classes don't seem to 
have a function in SHACL, so their purpose needs to be made clear. Why 
have a PropertyConstraint class?

Peter asks:
 >> What does it mean to be a class of something?  Even the new terminology
 >> section does not help, as it just opens up the question of how a class
 >> represents anything and how nodes can exist independent of any RDF 
graph.

I think I am asking the same question.

Next, property constraints are *definitions* that may be *applied* to 
properties in the focus node of the data graph during validation. The 
shapes graph is descriptive, but does not *do* anything. We have two 
sets of triples that are essentially inert; a 
program/application/implementation can use the rules/constraints in the 
shapes graph to test or validation whether the data graph meets those 
rules.

I don't know if this is what Peter means with:

 >> However, sh:minCount does not work this way, as it is about the set of
 >> values
 >> of a property.

kc


On 5/8/16 3:58 PM, Holger Knublauch wrote:
> On 7/05/2016 23:32, Peter F. Patel-Schneider wrote:
>> The wording in 2.3 is still problematic.  From that section:
>>
>> sh:PropertyConstraint is the class of all property constraints. Property
>> constraints apply on the value of a property on the focus node.
>>
>> However, sh:minCount does not work this way, as it is about the set of
>> values
>> of a property.
>>
>> What does it mean to be a class of something?  Even the new terminology
>> section does not help, as it just opens up the question of how a class
>> represents anything and how nodes can exist independent of any RDF graph.
>>
>> How do default value types interact with the terminology section?
>>
>>
>> What I am seeing here is a bunch of attempts to patch up something
>> that is a
>> poor design from the start.  It is thus no surprise that each attempt
>> only
>> exposes more and more problems and requires more and more machinery.
>
> I disagree completely. Anyway, we are currently starting bottom-up, with
> proper and official definitions of the basic terminology. Once we apply
> consistent terminology throughout the document, things will become
> clearer and cleaner.
>
> Holger
>
>
>

-- 
Karen Coyle
kcoyle@kcoyle.net http://kcoyle.net
m: 1-510-435-8234
skype: kcoylenet/+1-510-984-3600
Received on Monday, 9 May 2016 19:26:39 UTC

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