- From: Leo Sauermann <leo@gnowsis.com>
- Date: Tue, 15 Nov 2005 23:49:15 +0100
- To: public-rdf-dawg-comments@w3.org, Patrick.Stickler@nokia.com
Hello SPARQL, I have some input regarding the definition of DESCRIBE I have two inputs to make, explaination below: * Include Concise Bounded Descriptions as a "suggested" way the Query Processor handles calls to Describe (not authorative, the query processor MAY use CBD Semantics to gather the graph for describe) * Allow the passing of parameters to the query processor during describe calls =Background info= here is the current def from http://www.w3.org/TR/rdf-sparql-query/#describe "The query pattern is used to create a result set. The | DESCRIBE| form takes each of the resources identified in a solution, together with any resources directly named by IRI, and assembles a single RDF graph by taking a "description" from the target knowledge base. The description is determined by the query processor implementation and should provide a useful description of the resource, where the meaning of "useful" is determined by the information publisher." At the moment the definition of description is taken on the server side, by the query processor. We know from implementations, that Patrick Stickler's URIQA protocol defines Concise Bounded Descriptions with a similar intent, but with a concrete definition http://www.w3.org/Submission/CBD/ In our gnowsis project, a Semantic Desktop, the concept of CBDs proved very useful for practical implementation of a larger system. Also, in creation of adapters to extract information from heterogenous datasources, CBDs are useful. Hence, I would suggest to include the definition of CBDs so that implementers MAY use this semantic, and also that clients MAY hope that CBDs are returned. This would also give implementors a better definition of what they MAY do in their implementations, allowing to quick-start with existing code or at least an exact decision what is good here (and year-long experience). A notion of CBD and URIQA is, that the user can pass parameters to the query processor to ask for certain properties via passed parameters. http://sw.nokia.com/uriqa/URIQA.html#parameters These parameters include parameters like * format * naming * inference * reifications etc. We want to change some parts of our gnowsis software to URIQA, but cannot use the Describe syntax as a CBD replacement at the moment, because we cannot pass parameters through the query engine. One use case is crawling: When collecting data from a server to store it into a RDF database (using several URIQA/CBD calls) we pass parameters to indicate this use. The query engine should return then minimal graphs, that are connected to each other. Which is not important now, but we need to pass a parameter "crawling=true" through the engine, to our query engine implementation. Hence, even If the semantics of DESCRIBE is not clear, we would like to use it, but to pass name/value pairs through the engine so that we can refine the semantics of DESCRIBE a little. Passing parameters would allow us, to continue the CBD and URIQA system here and connect it to SPARQL, and also to continue our code base. Patrick Stickler can also comment on these requirements, we have chatted about this during the ISWC. greetings, hope that this email is useful input and helps us all, Leo Sauermann
Received on Tuesday, 15 November 2005 22:49:36 UTC