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

RE: Bookmarkable queries

From: Seaborne, Andy <andy.seaborne@hp.com>
Date: Fri, 14 May 2004 13:33:22 +0100
Message-ID: <E864E95CB35C1C46B72FEA0626A2E808031A93ED@0-mail-br1.hpl.hp.com>
To: Jos De_Roo <jos.deroo@agfa.com>, "'RDF Data Access Working Group'" <public-rdf-dawg@w3.org>

Jos,

To my reading of your example suggests the requriment for bookmarkability
(the concept, not necessary the URL mechanism).  That gives the ability to
record making a query request of a particular knowledge base.  The example
of asking the same query of a whole bunch of sources shows the case where
the query is reused in making requests to different sources,e.g. other
places recording the same information, using the same namespace  Both are
useful.

We have:

  Query ==> Query+target ==> Query request instance

i.e. a the query (no target) becomes a partially instantiated request
(query+target) then becomes used for the request.  There are cases for all
three (the last is useful for recording the action performed).

	Andy

-----Original Message-----
From: Jos De_Roo [mailto:jos.deroo@agfa.com] 
Sent: 13 May 2004 23:33
To: andy.seaborne@hp.com
Cc: 'RDF Data Access Working Group'; 'Rob Shearer'
Subject: RE: Bookmarkable queries

>> I think requirement 3.8 brings up major questions about just
>> what we consider a "query". Does a "query" include a
>> selection of the RDF source, or can the same query be
>> executed against different sources? (The latter seems much
>> more sensible to me...)
>
> +1 : I don't see why the query should need to record the
> execution but I can be persuaded by an example. At the moment,
> I see it as a protocol matter concerned more with selecting
> the service access point.

Although I was used to put the selection of the RDF source(s)
in the protocol (e.g. as command line arguments) I became more
convinced that putting them in the query expression is also
interesting. For a simple example that asks for the lat/long
coordinates of Chicago or Cambridge, see
http://eulersharp.sourceforge.net/2004/04test/danQ.n3
i.e.

@prefix owl: <http://www.w3.org/2002/07/owl#>.
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#>.
@prefix da: <http://eulersharp.sourceforge.net/euler#>.
@prefix d: <http://eulersharp.sourceforge.net/2004/04test/danP#>.

(d: owl: rdfs:).da:from da:select
    {{?C d:cityName "Cambridge";
         d:latitude ?LA;
         d:longitude ?LO} => {("Cambridge" ?LA ?LO) a d:Result}},
    {{?C d:cityName "Chicago";
         d:latitude ?LA;
         d:longitude ?LO} => {("Chicago" ?LA ?LO) a d:Result}}.

where that d: is actually one of the RDF sources
and the answer I actually got is

("Cambridge" 42.3 -71.1) a d:Result.
("Chicago" 41.9 -87.6) a d:Result.


-- 
Jos De Roo, AGFA http://www.agfa.com/w3c/jdroo/
Received on Friday, 14 May 2004 08:34:21 GMT

This archive was generated by hypermail 2.3.1 : Tuesday, 26 March 2013 16:15:19 GMT