On 26.02.2016 13:32, James Heald wrote:
These are used as placeholders for the meta-values "unknown value" and "no value" aren't they ?
Oh, right! I had not considered it to be possible that any subclass of statement would use "unknown value". All classes could at least be subclasses of "Entity" if nothing else can be said about them. For some of the cases in the list I found, it is also unclear why they should be classes at all.
Anyway, this at least clarifies that there is no problem with the RDF export/import here and instead we just have some strange data.
Markus
On 26/02/2016 12:27, Markus Kroetzsch wrote:
Hi Stas, hi all,
I just noted that BlazeGraph seems to contain a few erroneous triples. The following query, for example, returns a blank node "t7978245":
SELECT ?superClass WHERE { http://www.wikidata.org/entity/Q595133 p:P279/ps:P279 ?superClass }
https://query.wikidata.org/#SELECT%20%3FsuperClass%20WHERE%20%7B%0A%20%20%3C...
I stumbled upon six cases like this (for P279): Q595133 (shown above), Q1691488, Q11259005, Q297106, Q1293664, and Q539558. This would be less than 0.001% of the 623,963 P279 statements, but it's still enough to have application code trip over the unexpected return format ;-).
Best
Markus
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