Hi all,
after a tweet from Magnus [0] we talked a bit about entries without
statements (about 2.5M) and on the question if SPARQL could list all
entries in Wikidata that do not have statements. I played a bit with
combinations of OPTIONAL and FILTER-BOUND and FILTER NOT EXIST...
something like:
PREFIX wikibase: <http://wikiba.se/ontology#>
SELECT DISTINCT ?entry ?label ?statement WHERE {
?entry rdfs:label ?label . FILTER (lang(?label) = "en")
FILTER NOT EXISTS {
?statement ?prop ?entry ;
wikibase:rank ?rank .
}
} LIMIT 5
These queries tend to fail. Now, I'm not at all a SPARQL wizard and
maybe there is a simple way to not run into the time outs that I do
now.
But there was something else I noted... statements are not typed...
that would probably kick in some index, rather than the above query,
and the documentation actually speaks about wikibase:Statement [1] but
if I search for anything rdf:type-d as such, then it finds nothing in
the SPARQL end point:
https://query.wikidata.org/#PREFIX%20wikibase%3A%20%3Chttp%3A%2F%2Fwikiba.s…
Did this typing get lost at some point or is the documentation outdated?
Greetings,
Egon
0.https://twitter.com/MagnusManske/status/685499058228715520
1.https://www.mediawiki.org/wiki/Wikibase/Indexing/RDF_Dump_Format#Statemen…
--
E.L. Willighagen
Department of Bioinformatics - BiGCaT
Maastricht University (
http://www.bigcat.unimaas.nl/)
Homepage:
http://egonw.github.com/
LinkedIn:
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Blog:
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ORCID: 0000-0001-7542-0286
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