Given that this extension provides closure in SPARQL over RDF datasets,
is it now possible to form nested CONSTRUCTs over RDF datasets, or in
some other way specify a chain of RDF dataset queries?
I looked at the extended CONSTRUCT form, but I didn't see any spot to
plug in another CONSTRUCT to indicate the derived RDF dataset to be queried.
Tara
On 11/30/15 4:20 AM, Andy Seaborne wrote:
On 29/11/15 23:40, Tara Athan wrote:
> On a related note, I see that ARQ Construct quad could easily be
used > to construct quads where the name is a blank node. Having the quad
> name be a blank node is fine according to RDF
> http://www.w3.org/TR/rdf11-datasets/#sec-introduction (and is
> desirable in my usecase), but is not permitted according to SPARQL.
Yes, that should be there. I'll add it.
When it gets into TriG or N-Quads it will become a document-scoped
blank node only, as do any other blank nodes.
> Are such quads
> accepted in practice, or does this cause significant interoperability
> problems?
It's RDF 1.1 that has taken over defining RDF Datasets and the
syntaxes for them, which allow blank nodes for graphs. I presume that
any SPARQL revision by a W3C WG would remove the definition of RDF
Dataset from SPARQL and use the RDF 1.1 one in its place with all the
consequences. SPARQL should not take a different position on data.
There is a long standing wrinkle that blank nodes aren't allow by
syntax in GRAPH in a WHERE clause.
RDF 1.1 adds in a natural requirement for blank nodes in quad data
templates in the graph position.
It's in the SPARQL errata.
http://www.w3.org/2013/sparql-errata
(because I have just added it :-)
>
> Tara
ARQ supports blank node addressing for when you must.
IRI(blank node) returns a suitable IRI.
Andy
