- From: Irene Polikoff <irene@topquadrant.com>
- Date: Sat, 14 May 2016 13:05:29 -0400
- To: kcoyle@kcoyle.net
- Cc: Dimitris Kontokostas <kontokostas@informatik.uni-leipzig.de>, public-data-shapes-wg <public-data-shapes-wg@w3.org>
To me, this sounds like a question about what it means for a shape not to have a scope. One answer could be - such a shape is ignored. A shape is not evaluated against any nodes unless there is a scope. Another answer could be - it is then becomes applicable everywhere, meaning that any node in the data graph becomes a focus node for such a shape. What is the current approach? Sent from my iPhone > On May 14, 2016, at 11:53 AM, Karen Coyle <kcoyle@kcoyle.net> wrote: > > Another way to look at this is that there is a data graph that is to be addressed. If the data graph as a whole is not to be the target of the constraints, then one must apply a scope to define the subset of the graph that is the focus of the constraints. There is no change (AFAIK) in the function of the constraint between: > > > ex:MyShape > a sh:Shape ; > rdfs:comment "every dct:subject must have IRIs as objects" ; > sh:scopeClass ex:Class; > sh:property [ > sh:predicate dct:subject ; > sh:nodeKind sh:IRI ; > ] . > > and > > ex:MyShape > a sh:Shape ; > rdfs:comment "every dct:subject must have IRIs as objects" ; > sh:property [ > sh:predicate dct:subject ; > sh:nodeKind sh:IRI ; > ] . > > In both cases, the constraint applies to the scope of the shape; this can be either the entire data graph or a subset of the data graph. If the property constraint can function on a graph selected with rdf:type then it can function on the data graph as a whole. The pre-selection of every triple with property dct:subject seems unnecessary. It also seems hard to grasp because node and class scopes pinpoint a starting node for a graph while the property scope is going to return individual triples. These do not seem to be the same logical function. > > kc > > > >> On 5/14/16 5:07 AM, Dimitris Kontokostas wrote: >> Karen's example could be modeled with multiple shapes and property >> scopes or a single shape with allSubjectsScope and multiple sh:property >> definitions for dct:title & dct:subject which is more efficient >> >> Another gap that sh:AllSubjectsScope came to fill is sh:scopeClass >> rdfs:Resource that was available in very early versions of SHACL >> In general this scope gives shacl core the flexibility to define complex >> focus nodes using all subjects + filters that will not be easy otherwise >> so I would be keen on keeping this in core >> >> On Sat, May 14, 2016 at 7:22 AM, Karen Coyle <kcoyle@kcoyle.net >> <mailto:kcoyle@kcoyle.net>> wrote: >> >> Looking at this: >> >> On 5/13/16 5:23 PM, Holger Knublauch wrote: >> >> ex:MyShape >> a sh:Shape ; >> rdfs:comment "every dct:subject must have IRIs as objects" ; >> sh:scopeProperty dct:subject ; >> sh:property [ >> sh:predicate dct:subject ; >> sh:nodeKind sh:IRI ; >> ] . >> >> >> There is 100% redundancy between sh:scopeProperty and the >> constraint. If I were to state what I want to do in terms of >> validation, it would come out like this: >> >> >> ex:MyShape >> a sh:Shape ; >> rdfs:comment "every dct:subject must have IRIs as objects" ; >> sh:property [ >> sh:predicate dct:subject ; >> sh:nodeKind sh:IRI ; >> ] . >> >> because I am not using a scope at all. What this means is what is in >> the comment. A scope, logically, is a selection from the data graph, >> but this use case makes no such selection, and the constraint is >> sufficient. >> >> Is there a use of scopeProperty that would not be redundant? >> >> >> kc >> >> -- >> Karen Coyle >> kcoyle@kcoyle.net <mailto:kcoyle@kcoyle.net> http://kcoyle.net >> m: 1-510-435-8234 >> skype: kcoylenet/+1-510-984-3600 <tel:%2B1-510-984-3600> >> >> >> >> >> -- >> Dimitris Kontokostas >> Department of Computer Science, University of Leipzig & DBpedia Association >> Projects: http://dbpedia.org, http://rdfunit.aksw.org, >> http://aligned-project.eu >> Homepage: http://aksw.org/DimitrisKontokostas >> Research Group: AKSW/KILT http://aksw.org/Groups/KILT > > -- > Karen Coyle > kcoyle@kcoyle.net http://kcoyle.net > m: 1-510-435-8234 > skype: kcoylenet/+1-510-984-3600 >
Received on Saturday, 14 May 2016 17:06:00 UTC