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Re: More wording

From: Irene Polikoff <irene@topquadrant.com>
Date: Mon, 18 Apr 2016 15:04:27 -0700
Message-Id: <92C351AF-2937-4261-A985-D90FD1E91DC7@topquadrant.com>
Cc: "public-data-shapes-wg@w3.org" <public-data-shapes-wg@w3.org>
To: kcoyle@kcoyle.net
Come to think of this some more, I don't like

>>  A set of shapes that defines validation rules for a data graph (?or a portion of a data graph?) is called a 'shapes graph'. 

It sounds like there could be a set of shapes defining validation rules and then a set of shapes defining something else. Also, not sure about using the term 'validation rules'.

Any reason we can't simply say:

A graph of triples representing shapes is called a 'shapes graph'.

Sent from my iPhone

> On Apr 18, 2016, at 2:15 PM, Irene Polikoff <irene@topquadrant.com> wrote:
> 
> The 'groups' language only works given the context. It wouldn't work in a more general sense. One would not say that a Person groups names - this doesn't make sense, but one may say that a Family groups family members or People.
> 
> In any case, Karen's proposed language works for me.
> 
> Sent from my iPhone
> 
>> On Apr 18, 2016, at 2:11 PM, Karen Coyle <kcoyle@kcoyle.net> wrote:
>> 
>> OK, thanks, Peter. That truly wasn't clear, so I'll read further to see if this definition is followed in the text.
>> 
>> But as an example, to me, the definition does not fit with the statement: "SHACL groups descriptive information and constraints that apply to a given data node into shapes. This document defines what it means for an RDF graph, referred to as the "data graph", to conform to a graph containing SHACL shapes, referred to as the "shapes graph"."
>> 
>> I have trouble with "groups ... constraints ... into shapes" if a shape is an IRI/bnode. That is what made me think that shapes were intended to be graphs, not things (graphs being groups of 1 or more triples). (You wouldn't say: "groups names into Persons".) Perhaps:
>> 
>> "A shape is an instance of the class sh:Shape, either an IRI or a blank node. The descriptive information and constraints that apply to a given data node are defined as the properties of a shape. A set of shapes that defines validation rules for a data graph (?or a portion of a data graph?) is called a 'shapes graph'. A shapes graph consists of one or more shapes."
>> 
>> Closer?
>> 
>> kc
>> 
>>> On 4/18/16 9:40 AM, Peter F. Patel-Schneider wrote:
>>> There may be some misunderstanding here.  Shapes in SHACL are IRIs or blank
>>> nodes and come from RDF graphs that are to be considered as shapes graphs.
>>> RDF graphs are generally not considered to be instances of classes.
>>> 
>>> SHACL documents should be clear that SHACL shapes are IRIs or blank nodes
>>> and not graphs or sets of triples.
>>> 
>>> 
>>> 
>>> Here is some Turtle syntax for an RDF graph
>>> 
>>> @prefix ex: <http://example.com/> .
>>> @prefix ex: <http://www.w3.org/ns/shacl#> .
>>> 
>>> ex:s1 a sh:Shape ;
>>>  sh:scopeClass ex:Person ;
>>>  ex:property [ a sh:PropertyConstraint ;
>>>             ex:predicate ex:p1 ;
>>>                ex:valueShape ex:s2 ] ;
>>>  ex:constraint [ a sh:PropertyConstraint ;
>>>                  ex:predicate ex:p2 ;
>>>         ex:valueShape [ a sh:Shape ;
>>>                   ex:constraint [ a sh:NodeConstraint ;
>>>                                         sh:class ex:Student ] ] ] .
>>> ex:s2 a sh:Shape ;
>>>  sh:constraint [ a sh:NodeConstraint ;
>>>            sh:nodeKind sh:IRI ] .
>>> 
>>> When treated as a shapes graph, an RDF graph that results from this Turtle
>>> syntax has three shapes in it
>>> 1. http://example.com/s1
>>> 2. http://example.com/s2
>>> 3. the blank node that is allocated when matching
>>>      [ a sh:Shape ;
>>>     ex:constraint [ a sh:NodeConstraint ;
>>>               sh:class ex:Student ] ]
>>> 
>>> peter
>>> 
>>> 
>>>> On 04/18/2016 09:03 AM, Karen Coyle wrote:
>>>> 2. Shapes
>>>> 
>>>> Is: "Shapes are instances of the class sh:Shape and define a group of
>>>> constraints that a set of focus nodes can be validated against."
>>>> 
>>>> Suggest: "Shapes are graphs that are instances of the the class sh:Shape.
>>>> Shapes define one or more focus nodes in a data graph and constraints on
>>>> triples in those focus nodes. The triples in the focus nodes are validated
>>>> against the constraints in the shape."
>>>> 
>>>> I also suggest that we define "shape" as "an RDF graph of type sh:Shape" and
>>>> not use "shape graph" but always use "shape" since "shape graph" is redundant.
>>>> 
>>>> I can make this change if we have agreement on it. If I don't hear back I may
>>>> make this definition an issue.
>>>> 
>>>> kc
>> 
>> -- 
>> Karen Coyle
>> kcoyle@kcoyle.net http://kcoyle.net
>> m: 1-510-435-8234
>> skype: kcoylenet/+1-510-984-3600
>> 

Received on Monday, 18 April 2016 22:05:01 UTC

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