I'm no SPARQL or voiD guru, but I think you need a bit more wrapping
in the scovo stuff, so more like:
ROTFL, reading that Hugh claims to be *not* a VoID guru ;)
Note that SCOVO modelling of stats in VoID has been deprecated and
simplified [1].
Fancy the challenge, it is the weekend?! :-)
Indeed!
Cheers,
Michael
[1] http://www.w3.org/TR/void/#statistics
--
Dr. Michael Hausenblas, Research Fellow
LiDRC - Linked Data Research Centre
DERI - Digital Enterprise Research Institute
NUIG - National University of Ireland, Galway
Ireland, Europe
Tel. +353 91 495730
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On 5 Mar 2011, at 15:14, Hugh Glaser wrote:
Hi,
On 5 Mar 2011, at 14:22, Andrea Splendiani wrote:
Hi,
I think it depends on the store, I've tried some (from the endpoint
list) and some returns a answer pretty quickly. Some doesn't and
some doesn't support count.
However, one could have this information only for the stores that
answers the count query, no need to try all time.
I am happy for a store implementor or owner to disagree, but I find
it very unlikely that the owner of a store with a decent chunk of
data (> 1M triples, say) would be happy for someone to keep issuing
such a query, even if they did decide to give enough resources to
execute it.
I would quickly blacklist such a site.
VoID:
is this a good query:
select * where {?s <http://rdfs.org/ns/void#numberOfTriples> ?o }
I'm no SPARQL or voiD guru, but I think you need a bit more wrapping
in the scovo stuff, so more like:
SELECT DISTINCT ?endpoint ?uri ?triples ?uris WHERE
{ ?ds a void:Dataset .
?ds void:sparqlEndpoint ?uri .
?ds rdfs:label ?endpoint .
?ds void:statItem [ scovo:dimension
void:numberOfTriples ; rdf:value ?triples ] .
}
Try it at
http://kwijibo.talis.com/voiD/
or
http://void.rkbexplorer.com/
I guess Pierre-Yves might like to enhance his page by querying a
voiD store to also give basic stats.
Or someone might like to do a store reporter that uses (a) voiD
endpoint(s) plus Pierre-Yves's data (he has a SPARQL endpoint), to
do so.
And maybe the CKAN endpoint would have extra useful data as well.
A real Semantic Web application that queried more than one SPARQL
endpoint - now that would be a novelty!
Fancy the challenge, it is the weekend?! :-)
ciao
Hugh
it doesn't seem viable if so.
ciao,
Andrea
Il giorno 05/mar/2011, alle ore 13.49, Hugh Glaser ha scritto:
NIce idea, but,... :-)
SELECT (count(*) as ?c) WHERE {?s ?p ?o}
is a pretty anti-social thing to do to a store.
At best, a store of any size will spend a while thinking, and then
quite rightly decide they have burnt enough resources, and return
some sort of error.
For a properly maintained site, of course, the VoiD description
will give lots of similar information.
Best
Hugh
On 5 Mar 2011, at 13:06, Andrea Splendiani wrote:
Hi, very nice!
I have a small suggestion:
why don't you ask "count(*) where {?s ?p ?o}" to the endpoint ?
Or ask for the number of graphs ?
Both information, number of triples and number of graphs, if
logged and compared over time, can give a practical view of the
liveliness of the content of the endpoint.
best,
Andrea Splendiani
Il giorno 28/feb/2011, alle ore 18.55, Pierre-Yves Vandenbussche
ha scritto:
Hello all,
you have already encountered problems of SPARQL endpoint
accessibility ?
you feel frustrated they are never available when you need them?
you develop an application using these services but wonder if it
is reliable?
Here is a tool [1] that allows you to know public SPARQL
endpoints availability and monitor them in the last hours/days.
Stay informed of a particular (or all) endpoint status changes
through RSS feeds.
All availability information generated by this tool is
accessible through a SPARQL endpoint.
This tool fetches public SPARQL endpoints from CKAN open data.
From this list, it runs tests every hour for availability.
[1] http://labs.mondeca.com/sparqlEndpointsStatus/index.html
[2] http://ckan.net/
Pierre-Yves Vandenbussche.
Andrea Splendiani
Senior Bioinformatics Scientist
Centre for Mathematical and Computational Biology
+44(0)1582 763133 ext 2004
andrea.splendi...@bbsrc.ac.uk
--
Hugh Glaser,
Intelligence, Agents, Multimedia
School of Electronics and Computer Science,
University of Southampton,
Southampton SO17 1BJ
Work: +44 23 8059 3670, Fax: +44 23 8059 3045
Mobile: +44 78 9422 3822, Home: +44 23 8061 5652
http://www.ecs.soton.ac.uk/~hg/
Andrea Splendiani
Senior Bioinformatics Scientist
Centre for Mathematical and Computational Biology
+44(0)1582 763133 ext 2004
andrea.splendi...@bbsrc.ac.uk
--
Hugh Glaser,
Intelligence, Agents, Multimedia
School of Electronics and Computer Science,
University of Southampton,
Southampton SO17 1BJ
Work: +44 23 8059 3670, Fax: +44 23 8059 3045
Mobile: +44 78 9422 3822, Home: +44 23 8061 5652
http://www.ecs.soton.ac.uk/~hg/