Hi! > Suppose there is a property P that is a subproperty of Q and I query for > the Q properties of some object O that has values for both P and Q. > When I query for O's Q property values do I always get the P property > values as well?
It is possible to do such lookup but I don't think the query engine should/would be doing it by default, since such lookups would be pretty expensive - query about one property which is easily indexed can potentially explode into dozens of independent property queries which would be harder to efficiently look up. But maybe we can have a syntax that would do the expansion in cases where it is required. > > For example (using triples) > daughter subpropertyof child . > son subpropertyof child . > John son Bill . > John daughter Mary . > does a query for John's children return Bill and Mary? It is possible to make such kind of lookup, but it would probably be a two-stage lookup - i.e. first see if child has any subproperties, then lookup for children using the resulting list. We can have a syntax for this but I think it should be explicit - i.e. there should be a different way to ask for "child" and "child and everything beneath". The second way probably would be significantly more expensive. -- Stas Malyshev [email protected] _______________________________________________ Wikidata-tech mailing list [email protected] https://lists.wikimedia.org/mailman/listinfo/wikidata-tech
