Hi! > Unlike, most sites we do have our own custom frontend in front of > virtuoso. We did this to allow more styling, as well as being flexible > and change implementations at our whim. e.g. we double parse the SPARQL > queries and even rewrite some to be friendlier. I suggest you do the > same no matter which DB you use in the end, and we would be willing to > open source ours (it is in Java, and uses RDF4J and some ugly JSPX but > it works, if not to use at least as an inspiration). We did this to > avoid being locked into endpoint specific features.
It would be interesting to know more about this, if this is open source. Is there any more information about it online? > Pragmatically, while WDS is a Graph database, the queries are actually > very relational. And none of the standard graph algorithms are used. To If you mean algorithms like A* or PageRank, then yes, they are not used too much (likely also because SPARQL has no standard support for any of these, too), though Blazegraph implements some of them as custom services. > be honest RDF is actually a relational system which means that > relational techniques are very good at answering them. The sole issue is > recursive queries (e.g. rdfs:subClassOf+) in which the virtuoso > implementation is adequate but not great. Yes, path queries are pretty popular on WDQS too, especially given as many relationships like administrative/territorial placement or ownership are hierarchical and transitive, which often requires path queries. > This is why recovering physical schemata from RDF data is such a > powerful optimization technique [1]. i.e. you tend to do joins not > traversals. This is not always true but I strongly suspect it will hold > for the vast majority of the Wikidata Query Service case. Would be interesting to see if we can apply anything from the article. Thanks for the link! -- Stas Malyshev smalys...@wikimedia.org _______________________________________________ Wikidata mailing list Wikidata@lists.wikimedia.org https://lists.wikimedia.org/mailman/listinfo/wikidata
