W3C home > Mailing lists > Public > www-rdf-rules@w3.org > April 2003

SeRQL: new QL proposal + implementation result set format

From: Jeen Broekstra <jeen.broekstra@aidministrator.nl>
Date: Fri, 04 Apr 2003 13:53:46 +0200
Message-ID: <3E8D724A.3000700@aidministrator.nl>
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 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Monday, 7 December 2009 10:53:10 GMT