- From: Dimitris Kontokostas <kontokostas@informatik.uni-leipzig.de>
- Date: Thu, 17 Mar 2016 17:49:00 +0200
- To: "Peter F. Patel-Schneider" <pfpschneider@gmail.com>
- Cc: Holger Knublauch <holger@topquadrant.com>, Tom Johnson <johnson.tom@gmail.com>, RDF Data Shapes Working Group <public-data-shapes-wg@w3.org>
- Message-ID: <CA+u4+a0M2J2kC+VVpT2z0W9YadEBESwMZnEr0fQgMwYsvHN0bw@mail.gmail.com>
On Thu, Mar 17, 2016 at 3:20 PM, Peter F. Patel-Schneider < pfpschneider@gmail.com> wrote: > The diff seems to indicate that functions still work only over datasets, > although there is a TODO indicated. I was waiting for Holger to wake up and clarify this but you are right > Two "or dataset"s were also removed - > making the dataset optional is probably benign. > > As far as $shapesGraph goes, wording along the lines of "can be used to > access > the shapes graph" would seem to work, but would need some explanation along > the lines of "If the shapes graph is a named graph in the same dataset as > the > data graph then it can be accessed using its name in the dataset. > Otherwise a > SHACL engine would need to provide an alternative way to access the shapes > graph." > tried to fix all your comments in a second commit here https://github.com/w3c/data-shapes/commit/a0a52a4472d807683abf7cf104079f35272f27df this is a merge of both commits but also includes a few other editorial fixes https://github.com/w3c/data-shapes/compare/editorial-dk apologies for sending commits but I am not yet comfortable to commit to the main branch Best, Dimitris > > > peter > > > On 03/17/2016 02:04 AM, Dimitris Kontokostas wrote: > > I removed all mentions of dataset in the text that imply that validation > works > > on RDF datasets > > > https://github.com/w3c/data-shapes/commit/fa2d99fd61a473d14eef9cee57c0db1c61e03684 > > > > One thing left to decide and close this issue is how to refer to the > > '$shapesGraph" variable. right now we have variations of the following > in the spec > > "$shapesGraph ... a named graph IRI that contains the the shapes graph" > > > > reading the sparql spec, named graphs imply an RDF dataset: > > https://www.w3.org/TR/sparql11-query/#namedGraphs > > > > even if we remove the "named" and refer to them as just graphs, SPARQL > uses > > the "GRAPH" keyword in the "Querying the Dataset" section > > https://www.w3.org/TR/sparql11-query/#queryDataset > > > > so, do we still have an implicit assumption that validation works on RDF > datasets? > > > > Since we already have a resolution on $shapesGraph I see the following > options: > > a) we accept the edits as they are now in the spec and close this issue > > b) we try to weaken further the connection and change occurrences of > "named > > graph" to "graph" > > c) since this is sparql-specific issue, we can add a disclaimer in > section 1.2 > > > > regarding how a SHACL validation engine wraps graphs to perform > validation, it > > can be an implementation detail > > > > Dimitris > > > > > > On Wed, Mar 9, 2016 at 9:35 AM, Holger Knublauch <holger@topquadrant.com > > <mailto:holger@topquadrant.com>> wrote: > > > > Yes, you may have a point there - in cases like the default graph we > need > > to make sure that the system knows which subject to look for the > > sh:shapesGraph triples. This is probably just a URI parameter. > > > > (There are so many edit suggestions open right now that I am looking > > forward to sharing the workload with a second editor, now that > Arthur has > > left; yes I have a day job too.) > > > > Holger > > > > > > On 8/03/2016 11:02, Tom Johnson wrote: > >> > An RDF dataset is a purely conceptual entity. Many APIs implement > >> Dataset. Any Graph can be wrapped into a Dataset for execution, > even if > >> that Dataset is just virtual and only has a single graph in it. > >> > >> Reading the quoted text, this doesn't seem to hold. The "data graph" > >> links to the "shapes graph" via a triple with its graph name as the > >> subject. Many graphs do not have such a name (even those that are > within > >> Datasets; i.e. default graphs). > >> > >> Does SHACL provide a mechanism for connecting such a graph to a > shapes > >> graph? If not, how does wrapping the graph in a dataset within the > >> implementation help a SHACL user make this connection? > >> > >> - Tom > >> > >> On Mon, Mar 7, 2016 at 3:00 PM, Holger Knublauch < > holger@topquadrant.com > >> <mailto:holger@topquadrant.com>> wrote: > >> > >> An RDF dataset is a purely conceptual entity. Many APIs > implement > >> Dataset. Any Graph can be wrapped into a Dataset for execution, > even > >> if that Dataset is just virtual and only has a single graph in > it. > >> > >> Holger > >> > >> > >> > >> On 8/03/2016 2:45, RDF Data Shapes Working Group Issue Tracker > wrote: > >> > >> shapes-ISSUE-130 (rdf dataset assumption): SHACL should not > >> assume that the data graph is in an RDF dataset [SHACL Spec] > >> > >> http://www.w3.org/2014/data-shapes/track/issues/130 > >> > >> Raised by: Peter Patel-Schneider > >> On product: SHACL Spec > >> > >> """4. Declaring the Shapes Graph > >> > >> A data graph MAY link to one or more shapes graphs via the > >> property sh:shapesGraph. The subject of this predicate must > be > >> the graph resource, i.e. the name of the data graph in the > >> dataset. The objects of this predicate must be IRI nodes, > >> pointing at a named graph in the dataset. Tools may use this > >> information to determine which shapes graph to use for > >> validation. If present, tools SHOULD transitively follow any > >> links from the shapes graph via the predicate owl:imports to > >> other graphs and use the resulting union graph as parameter > to > >> the validation process.""" > >> > >> This assumes that the data graph is in an RDF dataset. > SHACL > >> validation should work on data graphs that are not in an RDF > >> dataset. > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> -- > >> -Tom Johnson > > > > > > > > > > -- > > Dimitris Kontokostas > > Department of Computer Science, University of Leipzig & DBpedia > Association > > Projects: http://dbpedia.org, http://rdfunit.aksw.org, > > http://http://aligned-project.eu <http://aligned-project.eu/> > > Homepage:http://aksw.org/DimitrisKontokostas > > Research Group: AKSW/KILT http://aksw.org/Groups/KILT > > > > -- Dimitris Kontokostas Department of Computer Science, University of Leipzig & DBpedia Association Projects: http://dbpedia.org, http://rdfunit.aksw.org, http:// http://aligned-project.eu Homepage:http://aksw.org/DimitrisKontokostas Research Group: AKSW/KILT http://aksw.org/Groups/KILT
Received on Thursday, 17 March 2016 15:49:55 UTC