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Re: CONSTRUCT an RDF Datest

From: Andy Seaborne <andy@apache.org>
Date: Mon, 30 Nov 2015 09:20:16 +0000
To: public-sparql-dev@w3.org
Message-ID: <565C14D0.7070407@apache.org>
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
Received on Monday, 30 November 2015 09:20:49 UTC

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