- From: Karen Coyle <kcoyle@kcoyle.net>
- Date: Sat, 16 Apr 2016 22:28:56 -0700
- To: "public-data-shapes-wg@w3.org" <public-data-shapes-wg@w3.org>
That doesn't work for me, because once again we have no definition of "shape" other than saying that it is an instance of sh:Shape, which makes it an instance of a class, and, AFAIK, an instance of a class cannot "point to" anything. I'm also pondering how a graph can contain instances of classes. It seems to me that a graph may have sub-graphs, and the subjects of those may be instances of classes, but it's gotta be triples all the way down. This seems to be a mixing of structure and semantics. For now, let's get the triples well-defined, and then we can worry about the semantics of classes. kc On 4/16/16 7:35 PM, Irene Polikoff wrote: > I think it is quite simple: > > * A SHACL shape is an instance of sh:Shape. A shape points to > constraints (or conditions) an RDF node is compared against to > determine if it conforms to the shape. For example, a shape > example:Issue may point to two constraints: one that says that the > property example:submitter must have exactly one value and the value > must be a string and one that says that the property > example:submissionDate must have exactly one value and the value > must be a date. > * When an RDF node conforms to conditions specified by a shape it is > said to be valid against a shape. > * A shape can also define what RDF nodes are to be validated (checked > for conformance) against it. This is called a scope of a shape. When > a shape doesn’t specify a scope, its scope is any RDF node. > > The specification also uses the following terminology: > > * RDF graph containing shapes is called “shapes graph”. > * RDF graph containing data to be checked for conformance (validated) > is called “data graph”. > * When examples talk about specific nodes that are being checked > against a shape, they use a term “focus node”. > * A report produced as a result of checking RDF data against the > relevant shapes is called a "validation report". > > > > Irene Polikoff, CEO > TopQuadrant, Inc. www.topquadrant.com <http://www.topquadrant.com/> > Technology providers making enterprise information meaningful > Blogs — http://www.topquadrant.com/the-semantic-ecosystems-journal/, > http://www.topquadrant.com/composing-the-semantic-web/ > LinkedIn — https://www.linkedin.com/company/topquadrant > Twitter - https://twitter.com/topquadrant > > > > > > On 4/16/16, 4:49 PM, "Karen Coyle" <kcoyle@kcoyle.net > <mailto:kcoyle@kcoyle.net>> wrote: > > I decided to take Peter's request that more people read through the > document, figuring that I would only be able to do a portion of it > before it got over my head. However, I haven't gotten very far due to > what I presume is some of that lack of consistency that Peter has > mentioned. > > The introduction (1.) has these sentences: > > "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"." > > "A shape may include a scope which defines which nodes in the data > graph > must conform to it. When a data node is checked for conformance to a > shape, that node is referred to as the focus node. The output of the > validation process is a validation report which indicates whether or > not > the data graph conforms to the shapes graph." > > In these we have "shapes", "SHACL shapes", "shapes graph", "nodes", > "data nodes" "focus nodes". > > Shortly thereafter we have "shape definitions", and a "shapes graph > that > defines these constraints has two shapes." > > The main problem is the use of "shape/shapes" some times and "shapes > graph" at others, with the implication (but not stated) that a "shapes > graph" can consist of one or more "shapes." However, I'm not sure > what a > shape is in this context, since it is by definition in the form of a > graph. > > Note also that the examples in that section consist of multiple graphs, > that is there is no subject that holds them together. I believe they > should have a symbolic "top node" that shows that they belong to a > single graph even though there are subgraphs. > > I'm happy to write alternate text for some of this, but in this case > I'm > not clear on what is intended. > > There are other areas where I can suggest better wording. I'd rather do > edits in a copy than try to explain them. Would that be ok? > > kc > > -- > Karen Coyle > kcoyle@kcoyle.net <mailto: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 Sunday, 17 April 2016 05:29:27 UTC