On 24.10.2015 12:29, Martynas Jusevičius wrote:
I don't see how cycle queries can be a requirement for SPARQL engines if they are not part of SPARQL spec? The closest thing you have is property paths.
We were talking about *cyclic data* not cyclic queries (which you can also create easily using BGPs, but that's unrelated here). Apparently, BlazeGraph has performance issues when computing a path expression over a cyclic graph.
Markus
On Sat, 24 Oct 2015 at 09:37, James Heald <j.he...@ucl.ac.uk <mailto:j.he...@ucl.ac.uk>> wrote: On 24/10/2015 00:50, Stas Malyshev wrote: > Hi! > >> least one Wikipedia) are considered to refer to equivalent classes on >> Wikidata, which could be expressed by a small subclass-of cycle. For > > We can do it, but I'd rather we didn't. The reason is that it would > require engine that queries such data (e.g. SPARQL engine) to be > comfortable with cycles in property paths (especially ones with + and > *), and not every one is (Blazegraph for example looks like does not > handle them out of the box). It can be dealt with, I assume, but why > create trouble for ourselves? It should be a basic requirement of any SPARQL engine that it should be able to handle path queries that contain cycles. For example, consider equivalence relationships like P460 "said to be the same as", which is being used to link given names together. If we want to find all the names in a particular equivalence class, and eg rank them by their incidence count, as is done in the 'query' columns at https://www.wikidata.org/wiki/Wikidata:WikiProject_Names/given-name_variants then being able to handle cycles in path queries is a basic requirement for the job. -- James. _______________________________________________ Wikidata mailing list Wikidata@lists.wikimedia.org <mailto:Wikidata@lists.wikimedia.org> https://lists.wikimedia.org/mailman/listinfo/wikidata _______________________________________________ Wikidata mailing list Wikidata@lists.wikimedia.org https://lists.wikimedia.org/mailman/listinfo/wikidata
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