W3C home > Mailing lists > Public > public-rdf-dawg@w3.org > October to December 2004

Re: tests and inference? (and UNSAID)

From: Pat Hayes <phayes@ihmc.us>
Date: Wed, 22 Dec 2004 14:58:13 -0800
Message-Id: <p06001f12bdefabb5c093@[]>
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?)


>  >
>>  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

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