- 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
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Received on Wednesday, 22 December 2004 23:04:08 UTC