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<?xml version="1.0" encoding="utf-8"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en"> <head> <title>Rasqal RDF Query Library</title> <link rel="meta" type="application/rdf+xml" title="DOAP" href="rasqal.rdf" /> </head> <body> <h1 style="text-align:center">Rasqal RDF Query Library</h1> <h2 style="text-align:center"><a href="http://purl.org/net/dajobe/">Dave Beckett</a></h2> <h2>Overview</h2> <p><a href="http://librdf.org/rasqal/">Rasqal</a> 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.</p> <p>Rasqal was designed to work closely with the <a href="http://librdf.org/">Redland RDF library</a> 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. </p> <p>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 <a href="TODO.html">todo list</a> for the current state information. A summary of the changes can be found in the <a href="NEWS.html">NEWS</a> file, detailed API changes in the <a href="RELEASE.html">release notes</a> and file-by-file changes in the CVS <a href="ChangeLog">ChangeLog</a>.</p> <p>Rasqal provides:</p> <ul> <li>An RDF <a href="docs/api/query.html">query</a> construction and access API.</li> <li>A query execution engine including constraint expression evaluation.</li> <li>A query result binding API.</li> <li>Query language support for <a href="http://www.w3.org/TR/2007/PR-rdf-sparql-query-20071112/">SPARQL</a>.</li> <li>Query language support for <a href="http://www.w3.org/Submission/2004/SUBM-RDQL-20040109/">RDQL</a>.</li> <li>Triple store querying APIs to support running over external RDF graphs.</li> <li>No memory leaks.</li> <li><a href="roqet.html">roqet</a> standalone RDF query utility program</li> </ul> <p>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 parser from <a href="http://librdf.org/raptor/">Raptor</a> and over a <a href="http://librdf.org/">Redland</a> indexed triple store. These can be called using the standalone <a href="roqet.html">roqet</a> query utility giving a query language identifier and query string to run the query over content described inside the query string (in RDQL, the <code>FROM</code> clause). </p> <p>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. </p> <h2>Supported Query Languages</h2> <h3>SPARQL Query Language for RDF</h3> <p>Rasqal provides support for the W3C SPARQL Query Language being developed by the W3C <a href="http://www.w3.org/2001/sw/DataAccess/">RDF Data Access Working Group</a>, as defined in <a href="http://www.w3.org/TR/2007/PR-rdf-sparql-query-20071112/">SPARQL Query Language for RDF</a>, W3C Proposed Recommendation 12 November 2007. It currently implements most of the functionality except for <code>GRAPH</code>, <code>UNION</code> and part of <code>OPTIONAL</code>. For detailed information on the implementation state, see the Rasqal <a href="TODO.html#sparql">todo / bugs list</a> and the <a href="http://bugs.librdf.org/">Redland issue tracker</a>.</p> <h3>RDF Data Query Language (RDQL)</h3> <p>Rasqal provides a complete implementation of the RDQL language, as defined in <a href="http://www.w3.org/Submission/2004/SUBM-RDQL-20040109/">RDQL - A Query Language for RDF</a>, W3C Member Submission 9 January 2004 based on the earlier versions in Jena defined in <a href="http://www.hpl.hp.com/semweb/rdql.htm">RDQL RDF Data Query Language</a> and the <a href="http://www.hpl.hp.com/semweb/rdql-grammar.html">RDQL Grammar</a>. The <a href="http://www.hpl.hp.com/semweb/doc/tutorial/RDQL/">Jena RDQL Tutorial</a> gives an introduction on the language. Rasqal currently passes all the <a href="http://jena.hpl.hp.com/2003/07/query/">Jena RDQL test suite</a> bar a couple. Detail of the status of the RDQL support is given in the <a href="http://bugs.librdf.org/">Redland issue tracker</a>.</p> <h3>LAQRS Adds to Querying RDF in SPARQL (LAQRS)</h3> <p> <a href="http://www.dajobe.org/2007/04/laqrs/">LAQRS</a> is an <b>experimental</b> 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. </p> <h2>Installation and Documentation</h2> <p>The public API is described in the <a href="librasqal.html">librasqal.3</a> UNIX manual page and in more detail in the <a href="docs/api/index.html">API reference</a>. It is demonstrated in the <a href="roqet.html">roqet</a> utility program which shows how to call the query engine and operate over the query results. When Rasqal is used inside <a href="http://librdf.org/">Redland</a>, the Redland documentation explains how to call the query engine and contains several example programs. </p> <p>To install Rasqal see the <a href="INSTALL.html">Installation document</a>. </p> <h2>Sources</h2> <p>The packaged sources are available from <a href="http://download.librdf.org/source/">http://download.librdf.org/source/</a> (master site) and also from the <a href="http://sourceforge.net/projects/librdf/">SourceForge site</a>. The development Subversion sources can also be <a href="http://svn.librdf.org/view/rasqal/">browsed with ViewCV</a>. </p> <p>Rasqal requires <a href="http://librdf.org/raptor/">Raptor</a> 1.4.0 or newer to build and run, which can be downloaded from the same area as the Rasqal source and binaries.</p> <h2>License</h2> <p>This library is free software / open source software released under the LGPL (GPL) or Apache 2.0 licenses. See <a href="LICENSE.html">LICENSE.html</a> for full details.</p> <h2>Mailing Lists</h2> <p>The <a href="http://librdf.org/lists/">Redland mailing lists</a> discusses the development and use of Rasqal and Redland as well as future plans and announcement of releases.</p> <hr /> <p>Copyright (C) 2003-2007 <a href="http://purl.org/net/dajobe/">Dave Beckett</a><br />Copyright (C) 2003-2005 <a href="http://www.bristol.ac.uk/">University of Bristol</a></p> </body> </html>