- From: Holger Knublauch <holger@topquadrant.com>
- Date: Fri, 14 Aug 2015 16:32:12 +1000
- To: public-data-shapes-wg@w3.org
You had stated the preference for your own document many times before. I don't think it is helpful at this stage to swap the meaning of terms such as Shape and Constraint. Doing such a renaming would likely push us back for several months, and make the whole discussion archive and history unusable. Holger On 8/14/2015 13:43, Peter F. Patel-Schneider wrote: > Here is my current preferred nomenclature. This has been excerpted from > https://www.w3.org/2014/data-shapes/wiki/Shacl-sparql with minor changes > (Core->Global, Extended->Scoped) and rearranged into a form that emphasizes > the nomenclature. Several details from the original account have been > elided. > > This only covers nomenclature and some high-level aspects of syntax and > validation. There is not just a change in naming of things from > http://w3c.github.io/data-shapes/shacl/ but also differences in how shapes > and constraints are put together and in how validation works. > > > > > SHACL constraints: > > Some SHACL constraints separate a constraint into a scope section and a > shape section. These SHACL constraints, called SHACL Scoped Constraints, > must have precisely one scope section and one or more shape sections. Both > the scope section and the shape sections are SHACL shapes. > > Other SHACL constraints have instead a SPARQL query and are called SHACL > Global Constraints. > > All SHACL constraints have as well a severity level. > > > SHACL shapes: > > There are multiple kinds of SHACL shapes, each with different syntax. Some > SHACL shapes have a component that is another SHACL shape. > > > Validating a SHACL shape against a node in an RDF graph (in an RDF dataset): > > The result of validating a SHACL shape against a node in an RDF graph (in an > RDF dataset) is zero or more shape violations. If no violations are in the > result then the validation succeeded, otherwise it failed. > > The different kinds of SHACL shapes each place different requirements on the > "shape" of an RDF graph in the neighbourhood of the node. The SHACL shapes > that have a component that is another SHACL shape generally succeed or fail > based on whether validating this other shape on one or more nodes in the > graph succeeds or fails. > > > Validating a SHACL Scoped Constraint: > > A SHACL scoped constraint is validated against an RDF graph (in an RDF > dataset) by first determining for which non-literal nodes in the graph the > constraint's scope succeeds. Then each of the constraint's shapes are > validated against each of these nodes. The validation succeeds as a whole > if each of these validations succeed and fails otherwise. > > > Validating a SHACL Global Constraint: > > A SHACL Global constraint is validated against an RDF graph (in an RDF > dataset) by evaluating its query against the graph (in the dataset). If the > query result is empty the validation succeeds and otherwise it fails. > > > Validating a SHACL constraint graph against an RDF graph (in an RDF dataset): > > A SHACL engine takes as arguments an RDF graph containing SHACL constraints > and an RDF graph (in an RDF dataset) containing information on which to > validate the constraints. A SHACL engine takes each node in the constraint > graph that is an instance of sh:Constraint and validates the constraint > encoded by this node against the information RDF graph. The validation > succeeds if no constraint with an error severity level fails and fails > otherwise. > >
Received on Friday, 14 August 2015 06:32:49 UTC