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Re: SPARQL Wishlist

From: Franck Michel <franck.michel@cnrs.fr>
Date: Mon, 1 Apr 2019 16:07:56 +0200
To: public-sparql-12@w3.org
Message-ID: <623f9aaa-408f-7daf-2e22-2d1ec97dd582@cnrs.fr>
Hi all,

Thx Jürgen for starting this thread. I'm continuing this wishlist 
discussion started on the internal-sparql-12 list:

- +1 on the whole reification question which is very urgently needed. 
RDF* and SPARQL* are certainly to be considered first.
- +1 on Jörn's proposition for datatype and language agnostic literal 
matches
- formal definition of the SERVICE + VAR pattern semantics, which is 
only informative in SPARQL 
1.1.(https://www.w3.org/TR/2013/REC-sparql11-federated-query-20130321/#variableService)
- formal position about how to handle the dereferencing of a named graph 
URI: should this return a few triples describing the named graph? Or 
should this return the content of the named graph? I personally would 
opt for the second option.
- related to the 2 previous points: enable querying dereferenceable RDF 
sources, not only other SPARQL endpoints. This could be an extension of 
the SERVICE clause semantics (see for instance SPARQL-LD [1]) or another 
clause. The idea is to leverage, from a SPARQL query, the content simply 
available on the web as dereferenceable RDF content for which no SPARQL 
endpoint is available.

[1] Fafalios P., Yannakis T. & Tzitzikas Y. (2016). Querying the Web of 
Data with SPARQL-LD. In Research and Advanced Technology for Digital 
Libraries vol. 9819, Fuhr, N., Kovács, L., Risse, T. & Nejdl, W. (Eds.), 
pp. 175–187. Cham. Springer International Publishing.

Franck.

Le 01/04/2019 à 15:55, Jürgen Jakobitsch a écrit :
> hi there,
>
> as indicated by andy, we should carry on with this conversation on the 
> public mailing list..
>
> i hereby restart the thread with my wishlist (i'm pretty sure there 
> also will be wiki page or other means to collect suggestions in the 
> near future) :-)
>
> 1. as a sucker of query optimization and the grand reducer of joins of 
> whatever sort, i really, really would appreciate
>    execution sequence hints or at the very least FROM in subqueries 
> and related a well defined sequence of what comes first: SERVICE or 
> subselect.
> 2. as a sucker of "words are flowing out like endless rain" (beatles: 
> across the universe) i fully support any forms of stream capabilities. 
> rdf is just made
>     for streams, a query type a la STREAM ?x FROM <http..> WHERE { ...
> 3. sometimes also very little things are required: a sequence (per 
> group or the whole result).. (this is for example possible with virtuoso)
> 4. vectorization on the fly would also be neat, we wanna do cool stuff 
> like ML, cooccurences, linguistic statistics,... don't we?
> 5. "split"..
>    or in general "set creating" functions.. this is usually only 
> possible with custom function these days, rdf4j for example requires 
> usage of an extended evaluation strategy, stardog can do it with 
> custom function,
>    as well as virtuoso with PL/SQL.. my preferred option would be 
> "split by regex"
>
> mtfbwy j
>
> *Jürgen Jakobitsch*
> Senior Technical Consultant
> Semantic Web Company GmbH
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Received on Monday, 1 April 2019 14:08:25 UTC

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