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Re: Simplification of scopes section (see also ISSUE-148)

From: Peter F. Patel-Schneider <pfpschneider@gmail.com>
Date: Sat, 14 May 2016 13:08:47 -0700
To: kcoyle@kcoyle.net, Irene Polikoff <irene@topquadrant.com>
Cc: Dimitris Kontokostas <kontokostas@informatik.uni-leipzig.de>, public-data-shapes-wg <public-data-shapes-wg@w3.org>
Message-ID: <25b6e82e-9d4d-6316-fb89-7cb07cfab2e0@gmail.com>
One problem with having all shapes initiate validation is that embedded shapes
would as well.

So in

ex:s1 rdf:type sh:Shape ;
  sh:scopeClass ex:Person ;
  sh:property [ sh:predicate ex:dependent ;
                sh:valueShape [ a sh:Shape ;
                                sh:property [ sh:predicate ex:SSN ;
                                              sh:minCount 1 ] ] ] .

the scope of the embedded shape would be all nodes in the data graph,
resulting in validation reports for any node that does not have a value for
ex:SSN.

If all shapes are to have scopes then there are ways around this problem.  One
would be that shapes are not embedded in other shapes.  Instead there would be
a new kind of SHACL thing that is used when the current effect of embedding
shapes in shapes is desired.

peter


On 05/14/2016 01:00 PM, Karen Coyle wrote:
> That may be what one interprets from the current spec, but it doesn't preclude
> us from considering the logic that I proposed, which is that a shape's scope
> is the data graph unless further scoping is defined. Obviously, this makes
> more sense to me than requiring a scope. Also, we do not at this point have a
> scope defined that would represent the entire data graph. How would I work
> with a set of triples with no defined classes and of which I could not know a
> priori the identity of a node?
> 
> I know this seems outlandish, but I'm thinking of the possibility of operating
> on received data that you need to investigate to see what state it is in. One
> role for validation is to analyze data sources that don't present with
> sufficient rigor or with pre-defined documentation. Some validation programs
> are going to have to work with unknowns and with bad data. This is one of the
> functions of validation in the massively shared cultural heritage community.
> One needs to be able to get some information out of data graphs that don't
> conform to expectations. It seems to me that being able to do some checking on
> the data graph as a whole could have value. (But I'll also check with my peeps
> about this and get back to this list.)
> 
> kc
> 
> 
> 
> On 5/14/16 12:23 PM, Irene Polikoff wrote:
>> Yes, this was my interpretation as well, but I wanted to confirm.
>>
>>
>> Irene
>>
>>
>>
>>
>>
>> On 5/14/16, 3:01 PM, "Peter F. Patel-Schneider" <pfpschneider@gmail.com>
>> wrote:
>>
>>> If a shape has no scopes then
>>> no validation is initiated by that shape.
>>
>>
>>
> 
Received on Saturday, 14 May 2016 20:09:16 UTC

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