Name Last modified Size Description
Parent Directory - AUTHORS 19-Feb-2006 09:32 31 COPYING 15-Jun-2006 22:01 18K COPYING.LIB 16-Jun-2005 16:32 26K ChangeLog 17-Dec-2009 03:31 130K INSTALL.html 27-Jun-2008 04:24 7.6K LICENSE-2.0.txt 16-Jan-2006 05:39 11K LICENSE.html 27-Jun-2008 04:24 3.4K LICENSE.txt 27-Jun-2008 04:24 2.7K NEWS 17-Dec-2009 03:31 8.1K NEWS.html 17-Dec-2009 03:26 13K NOTICE 16-Jan-2006 05:39 180 RELEASE.html 17-Dec-2009 03:26 87K
Rasqal is a free software / Open Source C library that handles Resource Description Framework (RDF) query syntaxes, query construction and query execution returning result bindings. The supported query languages are SPARQL and RDQL.
Rasqal was designed to work closely with the Redland RDF library but is entirely separate. It is intended to be a portable library working across many POSIX systems (Unix, GNU/Linux, BSDs, OSX, cygwin) win32 and others.
This is a beta quality library - the code is mature but the API is still changing and the SPARQL support is under active development. See the todo list for the current state information. A summary of the changes can be found in the NEWS file, detailed API changes in the release notes and file-by-file changes in the CVS ChangeLog.
Rasqal does not provide an RDF API or triple store, but relies on
external libraries implementing the triple store API providing
matched RDF data originally from a specified content URI. Rasqal
ships with triple store implementations using the output of an RDF
and over a
indexed triple store. These can be called using the standalone
query utility giving a query language
identifier and query string to run the query over content
described inside the query string (in RDQL, the
Rasqal also works inside Redland (0.9.17 or newer) to provide support for query languages, a query API and a result bindings API over graphs stored in Redland.
Rasqal provides support for the W3C SPARQL Query Language
being developed by the W3C
RDF Data Access Working Group,
as defined in
SPARQL Query Language for RDF, W3C Proposed Recommendation 12 November 2007.
It currently implements most of the functionality except for
UNION and part of
For detailed information on the implementation state, see the Rasqal
todo / bugs list
and the Redland issue tracker.
Rasqal provides a complete implementation of the RDQL language, as defined in RDQL - A Query Language for RDF, W3C Member Submission 9 January 2004 based on the earlier versions in Jena defined in RDQL RDF Data Query Language and the RDQL Grammar. The Jena RDQL Tutorial gives an introduction on the language. Rasqal currently passes all the Jena RDQL test suite bar a couple. Detail of the status of the RDQL support is given in the Redland issue tracker.
LAQRS is an experimental set of syntax extensions for SPARQL. The syntax and features may change at any time. At present Rasqal provides only parsing and API support for it.
The public API is described in the librasqal.3 UNIX manual page and in more detail in the API reference. It is demonstrated in the roqet utility program which shows how to call the query engine and operate over the query results. When Rasqal is used inside Redland, the Redland documentation explains how to call the query engine and contains several example programs.
To install Rasqal see the Installation document.
The packaged sources are available from http://download.librdf.org/source/ (master site) and also from the SourceForge site. The development Subversion sources can also be browsed with ViewCV.
Rasqal requires Raptor 1.4.0 or newer to build and run, which can be downloaded from the same area as the Rasqal source and binaries.
This library is free software / open source software released under the LGPL (GPL) or Apache 2.0 licenses. See LICENSE.html for full details.
The Redland mailing lists discusses the development and use of Rasqal and Redland as well as future plans and announcement of releases.
Copyright (C) 2003-2008 Dave Beckett
Copyright (C) 2003-2005 University of Bristol