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Re: Dealing with distributed nature of Linked Data and SPARQL

From: Mikel Egaña Aranguren <mikel.egana.aranguren@gmail.com>
Date: Wed, 8 Jun 2016 14:31:11 +0200
Message-ID: <CABf_9zKXjhheDhtXSAccfgZEaOCyueTJWJm+vk4qt5Vsd-FsSQ@mail.gmail.com>
To: Martynas Jusevičius <martynas@graphity.org>
Cc: public-lod <public-lod@w3.org>, public-declarative-apps@w3.org, James Anderson <james@dydra.com>, Arto Bendiken <arto@dydra.com>
Hi Martynas;

I thought that the majority of Linked Data servers work like Pubby, i.e.,
they serve Linked Data resources by doing a DESCRIBE on a Triple Store,
therefore serving the same triples. But it seems like you have encountered
the opposite (Different triples served) in many systems, do you have data
on how prevalent this issue is?


2016-06-08 14:06 GMT+02:00 Martynas Jusevičius <martynas@graphity.org>:

> Hey all,
> we are developing software that consumes data both from Linked Data
> and SPARQL endpoints.
> Most of the time, these technologies complement each other. We've come
> across an issue though, which occurs in situations where RDF
> description of the same resources is available using both of them.
> Lest take a resource http://data.semanticweb.org/person/andy-seaborne
> as an example. Its RDF description is available in at least 2
> locations:
> - on a SPARQL endpoint:
> http://xmllondon.com/sparql?query=DESCRIBE%20%3Chttp%3A%2F%2Fdata.semanticweb.org%2Fperson%2Fandy-seaborne%3E
> - as Linked Data: http://data.semanticweb.org/person/andy-seaborne/rdf
> These descriptions could be identical (I haven't checked), but it is
> more likely than not that they're out of sync, complementary, or
> possibly even contradicting each other, if reasoning is considered.
> If a software agent has access to both the SPARQL endpoint and Linked
> Data resource, what should it consider as the resource description?
> There are at least 3 options:
> 1. prioritize SPARQL description over Linked Data
> 2. prioritize Linked Data description over SPARQL
> 3. merge both descriptions
> I am leaning towards #3 as the sensible solution. But then I think the
> end-user should be informed which part of the description came from
> which source. This would be problematic if the descriptions are
> triples only, but should be doable with quads. That leads to another
> problem however, that both LD and SPARQL responses are under-specified
> in terms of quads.
> What do you think? Maybe this is a well-known issue, in which case
> please enlighten me with some articles :)
> Martynas
> atomgraph.com
> @atomgraphhq

Mikel Egaña Aranguren, Ph.D.

Received on Wednesday, 8 June 2016 12:31:43 UTC

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