- From: Stephane Fellah <stephanef@imagemattersllc.com>
- Date: Fri, 13 May 2005 14:28:30 -0400
- To: <public-rdf-dawg-comments@w3.org>
Dan, Thanks for answering my comments. The FROM approach is valid only if the client has the ability to serve the premises from a URI. This requires from the server the ability to resolve the URI, establish the connection to a server and fetch the data using a specific protocol. On client side, this would require to store the data on a an external server (web server ?). This approach requires a lot of infrastructure to put in place. There are many case when clients generates premises in memory and want to communicate directly with local query engine (ARQ for example and not from the web). For example, a client may draw a polygon on a map and asks the KB server to provide all the Point of Interest within this polygon. The SPARQL language should provide a mechanism to pass this polygon inline in the query. My proposal is addressing this need. I think the protocol should support both remote reference and inline premises. >One implementation strategy that is consistent with the specification >is for the engine to index its dataset before receiving queries and >not handle on-the-fly additional premises. I do not see how this could be accomplish, if the interactive client generates premises on the fly (like the polygon drawn on the map). Best regards Stephane Fellah Image Matters LLC -----Original Message----- From: Dan Connolly [mailto:connolly@w3.org] Sent: Thursday, May 12, 2005 10:22 AM To: Stephane Fellah; public-rdf-dawg-comments@w3.org Subject: Re: User defined operations and PREMISES keyword Sorry for the delay in responding to your comment of 20 Apr 2005 http://lists.w3.org/Archives/Public/public-rdf-dawg-comments/2005Apr/0038.ht ml > I am currently trying to create user-defined spatial operators for SPARQL. Interesting! [...] > It seems to me that the current specification does not provide a way to pass the description of p1 in the query [...] > To support this query, SPARQL needs a mechanism to pass the user defined > triples, so they could be added as premises in the query engine (DQL is > using such concept) prior to the evaluation on any graph. Note that the FROM keyword is back in the recent draft... http://www.w3.org/TR/2005/WD-rdf-sparql-query-20050419/#specifyingDataset which allows specifying premises by reference. > The handling of > the premises would be pretty straightforward to implement by any SPARQL > query engine. One implementation strategy that is consistent with the specification is for the engine to index its dataset before receiving queries and not handle on-the-fly additional premises. > ISSUE 2: OPTIONAL OR NULL PARAMETERS. > ISSUE 3: DESCRIPTION OF SUPPORTED FUNCTIONS IN SPARQL PROTOCOL. More on those separately... -- Dan Connolly, W3C http://www.w3.org/People/Connolly/ D3C2 887B 0F92 6005 C541 0875 0F91 96DE 6E52 C29E see you at XTech in Amsterdam 24-27 May?
Received on Saturday, 14 May 2005 04:03:12 UTC