- From: Markus Lanthaler <markus.lanthaler@gmx.net>
- Date: Tue, 23 Jun 2015 21:45:11 +0200
- To: "'Hydra'" <public-hydra@w3.org>
On 23 Jun 2015 at 13:05, Ruben Verborgh wrote: >> Strictly speaking it is not necessary but obviously it makes certain queries >> more efficient. Is that increased efficiency necessary or can we move this >> "feature" to the client? In other words, can we replace >> >> ?x foaf:knows ?x >> queries with >> >> __ foaf:knows __ >> ___ is a completely arbitrary value, i.e., the server returns all triples >> that contain foaf:knows in the predicate position. > > Well, in the worst case it could be very inefficient, > i.e., there could be 5,000,000,000 knows relations > but no person who knows themselves. Agreed. > But I think this is orthogonal to query execution: > what is done with the interface is not as relevant here, > since query execution is only one of the possible alternatives. > > The question is about the interface itself: how expressive should it be? > If we say "triple patterns", I believe we should really go for triple patterns. > It would be a pity we could not go there because the interface doesn't allow it. Let's separate this issue into two: the value space of VariableRepresentation and TPF interface. >> RDF terms have no notion of placeholders or variables. > > Yes, but they are a quite universal concept in IT in general. > > Actually, we could restate the pattern as > _:x foaf:knows _:x > and then we only use RDF terms. > > Would that be acceptable? Haven't thought about that. But you are right, that should work.... and I think I would prefer that. Do you see any problems with going down that route? -- Markus Lanthaler @markuslanthaler
Received on Tuesday, 23 June 2015 19:45:43 UTC