- From: Karen Coyle <kcoyle@kcoyle.net>
- Date: Sat, 14 May 2016 11:44:04 -0700
- To: Irene Polikoff <irene@topquadrant.com>
- Cc: Dimitris Kontokostas <kontokostas@informatik.uni-leipzig.de>, public-data-shapes-wg <public-data-shapes-wg@w3.org>
On 5/14/16 10:05 AM, Irene Polikoff wrote: > 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? The document does not address this. Therefore, we do not have one. - kc > > 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 >> > -- 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 18:44:29 UTC