- From: Ogbuji, Chimezie <OGBUJIC@ccf.org>
- Date: Thu, 11 Oct 2007 15:14:44 -0400
- To: public-rdf-dawg@w3.org
- Message-ID: <2702D0EBA4F0A749968E52E8644184EA28880C@CCHSCLEXMB59.cc.ad.cchs.net>
Per my action [1] to propose text to clarify that not all graphs in the dataset need to be disjoint/distinct. The text below is meant to extend the last paragraph of 8.2.2 Specifying Named Graphs. This seemed to be the best place for the clarification. I tried to cover the general ambiguity. [[ The FROM NAMED syntax suggests that the IRI identifies the corresponding graph, but the relationship between an IRI and a graph in an RDF dataset is indirect. The IRI identifies a resource, and the resource is represented by a graph (or, more precisely: by a document that serializes a graph). The relationship between the IRI and the representation is subject to time, an intermediate caching policy, the query service, and the mechanics of the underlying transport protocol. For further details see [WEBARCH]. The distinction between a surface RDF notation and the abstract RDF graph which results from parsing an instance of the surface notation is an additional indirection. As a consequence of these things, the repeated use of an IRI in either the same dataset clause, across dataset clauses, or across whole SPARQL queries can feasibly result in either the formulation of a single canonical graph, separate but isometric graphs, or completely disjoint [2] RDF graphs for each use of the same IRI. ]] [1] http://www.w3.org/2007/10/09-dawg-minutes.html#action14 [2] http://www.w3.org/TR/rdf-concepts/#section-graph-equality Chimezie (chee-meh) Ogbuji Lead Systems Analyst Thoracic and Cardiovascular Surgery Cleveland Clinic Foundation 9500 Euclid Avenue/ W26 Cleveland, Ohio 44195 Office: (216)444-8593 ogbujic@ccf.org =================================== Cleveland Clinic is ranked one of the top hospitals in America by U.S. News & World Report (2007). 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 Thursday, 11 October 2007 19:15:20 UTC