Re: SHACL to SPARQL

Hi Tom,

Really like the library, the playground helps a lot with testing
ideas/understanding too. I'll email you separately re. trying to reproduce
some of my queries.

I've done things like sh:maxCount = 0 to represent excluded properties but
this feels a little unintended/hacky.

Thanks,


On Tue, Sep 24, 2024 at 5:49 PM Tomasz Pluskiewicz <tomasz@t-code.pl> wrote:

> Hi David
>
> I’m the author of hypermedia-app/shape-to-query. Happy to compare notes on
> query generation any time.
>
> I felt like adding the custom SPORule is generally a safe thing to do
> because ultimately, to generate a query is quite an isolated use case.
>
> That said, I do agree with you that SPARQL seems to be missing the means
> to more accurately define properties. A catch-all is the extreme but I also
> found myself missing something like an “all except X” path. See
> https://github.com/w3c/shacl/issues/20
>
> Good day,
> Tom
>
>
> On 24 September 2024 at 01:50:18, David Habgood (dcchabgood@gmail.com)
> wrote:
> > Thanks for the links, I'll have a play with those and see if I can
> generate
> > the sorts of queries I'm using.
> > I was linked to some work recently
> > https://github.com/hypermedia-app/shape-to-query which had similar
> > extensions to what I've added e.g.
> > https://shape-to-query.hypermedia.app/docs/#extension-spo-rule - this
> > prompted me to ask.
> >
> > The other context for the work I'm doing is it needs to combine a number
> of
> > things to generate SPARQL queries, some of which are specified in SHACL,
> > some not. To do this I've implemented the SPARQL Grammar as a set of
> Python
> > Pydantic models (
> >
> https://github.com/Kurrawong/sparql-grammar-pydantic/tree/david/wip-complete-grammar/sparql_grammar_pydantic),
>
> > which makes it conceptually easy/safe to merge the different inputs and
> > generate valid/performant SPARQL queries. I might look to extend one of
> the
> > existing libraries to optionally produce SPARQL Grammar.
> >
> > On Tue, Sep 24, 2024 at 5:43 AM Kurt Cagle wrote:
> >
> > > Also, Flores Bakker has been working on an rdf representation of sparql
> > > that is coming along very well. There may be some overlap here.
> > >
> > > On Mon, Sep 23, 2024, 12:40 Kurt Cagle wrote:
> > >
> > >> This looks like it may be incredibly useful.
> > >>
> > >> On Mon, Sep 23, 2024, 12:07 Vladimir Alexiev <
> > >> vladimir.alexiev@ontotext.com> wrote:
> > >>
> > >>> These may be useful:
> > >>>
> > >>> https://shape-fragments.github.io/shape-fragments-spec/
> > >>> https://github.com/Shape-Fragments/SHACL2SPARQL
> > >>> https://github.com/MaximeJakubowski/ssf_project
> > >>> https://github.com/MaximeJakubowski/sls_project
> > >>>
> > >>>
> > >>> On Mon, Sep 23, 2024 at 2:57 PM David Habgood
> > >>> wrote:
> > >>>
> > >>>> Hi all,
> > >>>>
> > >>>> I have a library which generates SPARQL queries from SHACL, mostly
> to
> > >>>> support two use cases. The first is listing sets of items, or focus
> nodes,
> > >>>> with constraints on which items are selected. I find this one quite
> > >>>> straightforward in SHACL. The second is describing individual
> objects, i.e.
> > >>>> which properties should be included/and or excluded when describing
> an
> > >>>> individual focus node. This one I find less clear - I can see there
> are a
> > >>>> series of SHACL predicates which are relevant, but it's unclear to
> me if
> > >>>> there's a "canonical" way this should be done.
> > >>>>
> > >>>> My question is whether there's a canonical way to do Use Case 2,
> and if
> > >>>> not, should this form part of the use cases SHACL covers in future
> or be a
> > >>>> part of a SHACL extension.
> > >>>>
> > >>>> In detail my use cases are:
> > >>>>
> > >>>> Use Case 1:
> > >>>> I want to describe the selection of a set of focus nodes, based on
> one
> > >>>> or a combination of the following focus node attributes:
> > >>>> - the class of the focus nodes
> > >>>> - the focus nodes' relationship to a specified node (e.g. is member
> of
> > >>>> x)
> > >>>> - the focus nodes' relationship to nodes of a specified class (e.g.
> the
> > >>>> dcat:Catalogs that contain any dcat:Dataset, dcat:Resource etc.)
> > >>>> - the presence or abscence of properties on the focus nodes,
> including
> > >>>> via path relations (inverse, sequence etc.)
> > >>>>
> > >>>> Use Case 2:
> > >>>> I want to describe a focus node by choosing one of the following two
> > >>>> methods:
> > >>>> 1.
> > >>>> a. including all direct properties, except:
> > >>>> - excluding any properties explicitly stated including via path
> > >>>> relations (inverse, sequence etc.). (e.g. when describing a
> dcat:Dataset,
> > >>>> not listing it's large number of members)
> > >>>> - including any properties explicitly stated via "indirect" path
> > >>>> relations (inverse, sequence etc.)
> > >>>> b. inclusion of blank nodes to a specified depth
> > >>>>
> > >>>> 2.
> > >>>> a. excluding all direct/indirect properties, except:
> > >>>> - including any properties explicitly stated via direct and indirect
> > >>>> path relations (inverse, sequence etc.)
> > >>>> b. inclusion of blank nodes to a specified depth
> > >>>>
> > >>>> If SHACL predicates are reused across both use cases I want a clear
> way
> > >>>> to distinguish which they are being used for. E.g. is a SHACL
> expression
> > >>>> which in some way specifies dcterms:hasPart being used to describe
> how to
> > >>>> select a set of focus nodes, or how to describe each focus node. At
> present
> > >>>> I've used extension predicates for the blank node depth and
> "include all
> > >>>> properties" concepts.
> > >>>>
> > >>>> Thanks,
> > >>>> David
> > >>>>
> > >>>
> >
>
>