- From: Chimezie Ogbuji <ogbujic@ccf.org>
- Date: Mon, 30 Mar 2009 19:54:15 -0400
- To: "Seaborne, Andy" <andy.seaborne@hp.com>, "Lee Feigenbaum" <lee@thefigtrees.net>
- cc: "Kjetil Kjernsmo" <Kjetil.Kjernsmo@computas.com>, "'RDF Data Access Working Group'" <public-rdf-dawg@w3.org>
This is purely anecdotal, but meant to inform this thread regarding Querying "all graphs" and allowing services to interpret the IRIs in dataset clauses in special ways. I recently wanted to use an OWL editor (with a SPARQL composer) to compose SPARQL queries and dispatch it against a SPARQL service I setup. I was told that in order to do this, rather than configure the editor to tell it which location to send the queries to I had to add: FROM <..URL of endpoint..> to the query, so both the client and the server interpret the use of FROM clause. For the client, it uses this to determine where to 'send' the query (I'm not sure if this a fair reading of SPARQL). For the service, it assumes dataset IRIs that refer to the service can be ignored. At first, I thought this was not the best way to do this, but upon closer reading of the specification, this *seems* to be allowed, since the service could determine that it is the resource identified by the endpoint URL and thus answering the query using the system-level dataset is tantamount to creating the default graph out of whatever representation might be returned from the endpoint URL (even though resolving the endpoint URL over HTTP would return an HTML form, for instance). However, in order to have my service properly answer to queries composed and dispatched from this editor, I had to change the functionality such that whenever the default dataset IRI is the location of the endpoint, the result is essentially a 'no-op'. Prior to making this change, my service was actually trying to resolve the endpoint URL in order to get a graph representation, parse the representation (in this case it wasn't able to parse the HTML form), and evaluating the query against an empty graph. If there were some best practices about such liberties services can take with 'interpreting' IRI in FROM / FROM NAMED it might help guide making such a change to a service implementation in order to be able to align its understanding of endpoint URLs with that of this particular client. ---------------------- Chimezie (chee-meh) Thomas-Ogbuji (oh-bu-gee) Heart and Vascular Institute (Clinical Investigations) Cleveland Clinic (ogbujic@ccf.org) Ph.D. Student Case Western Reserve University (chimezie.thomas-ogbuji@case.edu) =================================== P Please consider the environment before printing this e-mail Cleveland Clinic is ranked one of the top hospitals in America by U.S. News & World Report (2008). Visit us online at http://www.clevelandclinic.org for a complete listing of our services, staff and locations. Confidentiality Note: This message is intended for use only by the individual or entity to which it is addressed and may contain information that is privileged, confidential, and exempt from disclosure under applicable law. If the reader of this message is not the intended recipient or the employee or agent responsible for delivering the message to the intended recipient, you are hereby notified that any dissemination, distribution or copying of this communication is strictly prohibited. If you have received this communication in error, please contact the sender immediately and destroy the material in its entirety, whether electronic or hard copy. Thank you.
Received on Monday, 30 March 2009 23:55:03 UTC