- From: Jeen Broekstra <jeen.broekstra@aidministrator.nl>
- Date: Fri, 04 Apr 2003 13:53:46 +0200
- To: www-rdf-rules@w3.org
Hi all, A couple of IRC meetings ago I promised to send some docs about a query language proposal that we were working on in Sesame, which supports both variable-binding and (sub)graph result sets. Here is a link to a draft user manual for this proposal: http://sesame.aidministrator.nl/publications/SeRQL%20user%20manual.pdf Fortunately, we can do a bit better than just a document. There is a prototype implementation available on the Sesame demonstration site: http://sesame.aidministrator.nl/sesame/ You can play around with the query engine on one of the public repositories, or we can create a test repository for you if you wish to test it on your own data. For now named SeRQL (pronounce "Circle", for Sesame RDF Query Language), the aim of the proposal is to combine the best features of existing (query) languages like RQL, RDQL, N-Triples and N3. A lot of experience that we got from implementing engines for both RQL and RDQL and from user feedback has gone into the design. The main features of SeRQL are: * Convenient path expressions a la RQL, but less complex syntax. * Support for variable-binding queries (aka SELECT-queries), as well as queries that return real RDF graphs (aka CONSTRUCT-queries). The CONSTRUCT-queries allow you to extract subgraphs from a repository, or to construct new RDF graphs that are derived from the original (somewhat comparable to views in SQL). * Support for datatyped literals. * Functions for filtering literal values based on their language and/or datatype. * Functions for filtering values based on whether the value is a resource or a literal. Added bonus is that the variable-binding result set implements the proposed query result set format from Andy Seaborne: http://www.w3.org/2003/03/rdfqr-tests/recording-query-results.html We encourage you to take a look at the proposal and we would very much welcome feedback on it. Best regards, Jeen & Arjohn -- jeen.broekstra@aidministrator.nl aidministrator nederland bv - http://www.aidministrator.nl/ julianaplein 14b, 3817 cs amersfoort, the netherlands tel. +31-(0)33-4659987, fax. +31-(0)33-4659987
Received on Friday, 4 April 2003 06:55:48 UTC