- From: Pat Hayes <phayes@ihmc.us>
- Date: Wed, 22 Dec 2004 14:58:13 -0800
- To: Steve Harris <S.W.Harris@ecs.soton.ac.uk>
- Cc: RDF Data Access Working Group <public-rdf-dawg@w3.org>
>On Wed, Dec 22, 2004 at 10:32:11 +0000, Andy Seaborne wrote: >> >>FROM could make sense - the server offers a numer of graphs and the >> >>URI in teh FROM must choose one of them. If it names some graph the >> >>server is not publishing, then the query generates an error. FROM >> >>isn't a requirements to load any graph (I worry about the security >> >>issues of that). A server may require that there is only one URI in >> >>the FROM clause - i.e. no arbitrary RDF merge of graphs. It is just a >> >>request for something that the server does not offer. >> > >> > >> >Agreed. I think we should allow a server to refuse to answer a query if >> >it names FROM a graph that the server cannot (prefers not to) access, >> >and we should allow the query to provide a variable in the FROM position >> >which gets bound to the name of the source as part of the answer, so >> >that a query can say, in effect: answer this from any source you choose, >> >but tell me what the source was. >> >> Woudl using "SOURCE ?src { ... query pattern ... }" achived this effect if >> the query is over the collection of named graphs? > >I would hope so, named grpahs or not. > >> >Query-answering servers should be >> >required to provide a binding to any such variable, even if it is a >> >'trivial' one which simply identifies the server itself (which means, >> >roughly: I am the source, and that's all you are going to get out of me >> >on that topic.) >> >> Interesting - this is saying the default graph has a URI. Default graph?? That sounds like a horrible idea. Where did that come from? I don't remember seeing anything in the draft about default graphs. (What is entailed by the default graph? Or would those only be default entailments? If I already have a graph, can I import the default graph into it by default?) Pat > > >> I wonder how that interacts with the protocol. > >I interpreted that part of the protocol as refering to the KB level, ie. >the level at which triples dont interact. Though I contradicted that in a >previous mail. Must learn to stop sending mail pre-coffee. > >- Steve -- --------------------------------------------------------------------- IHMC (850)434 8903 or (650)494 3973 home 40 South Alcaniz St. (850)202 4416 office Pensacola (850)202 4440 fax FL 32502 (850)291 0667 cell phayes@ihmc.us http://www.ihmc.us/users/phayes
Received on Wednesday, 22 December 2004 23:04:08 UTC