- From: Steve Harris <steve.harris@garlik.com>
- Date: Thu, 26 Apr 2012 15:27:46 +0100
- To: Richard Cyganiak <richard@cyganiak.de>
- Cc: Sandro Hawke <sandro@w3.org>, public-rdf-wg WG <public-rdf-wg@w3.org>
On 2012-04-25, at 21:45, Richard Cyganiak wrote: > Hi Steve, > > On 25 Apr 2012, at 19:54, Steve Harris wrote: >>> @union is just syntactic sugar in TriG, shorthand for having to >>> repeat all the triples in all the named graphs. >>> >>> Does that change your mind about it, at all? >> >> Not really. >> >> The implication of that would be that if I see @union I have to disable an optimisation that's designed specifically to handle that (common) case. > > Why do you need to disable the optimisation? If your store has the optimisation (union default graph), then you already know that it will automatically do what @union asks for, so you just have to load the named graphs and are done. > > If your store *didn't* have a union default graph, only then it would have to do something special when it sees @union: load every triple twice, both into a named graph and into the default graph. Either way you're screwed - see my other mail. >> I don't see how it makes ay sense to allow a data format to specify that behaviour, it should normally be up to the query author. > > @union doesn't specify behaviour. It specifies what triples are in the default graph of the serialized dataset. It doesn't dictate what happens when you load that dataset into a store. That's not the impression I get by reading the examples. If it /doesn't/ alter the behaviour of the store then it's useless, the query engines default behaviour will just make it moot. - Steve -- Steve Harris, CTO Garlik, a part of Experian 1-3 Halford Road, Richmond, TW10 6AW, UK +44 20 8439 8203 http://www.garlik.com/ Registered in England and Wales 653331 VAT # 887 1335 93 Registered office: Landmark House, Experian Way, Nottingham, Notts, NG80 1ZZ
Received on Thursday, 26 April 2012 14:28:26 UTC