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170 lines
6.5 KiB
HTML
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
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<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en">
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<head>
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<title>Rasqal RDF Query Library</title>
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<link rel="meta" type="application/rdf+xml" title="DOAP" href="rasqal.rdf" />
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</head>
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<body>
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<h1 style="text-align:center">Rasqal RDF Query Library</h1>
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<h2 style="text-align:center"><a href="http://www.dajobe.org/">Dave Beckett</a></h2>
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<h2>Overview</h2>
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<p><a href="http://librdf.org/rasqal/">Rasqal</a>
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is a free software / Open Source C library that handles Resource
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Description Framework (RDF) query syntaxes, query construction and
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query execution returning result bindings. The supported query
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languages are SPARQL and RDQL.</p>
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<p>Rasqal was designed to work closely with the
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<a href="http://librdf.org/">Redland RDF library</a>
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but is entirely separate. It is intended to be a portable library
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working across many POSIX systems (Unix, GNU/Linux, BSDs, OSX, cygwin)
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win32 and others.
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</p>
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<p>This is a beta quality library - the code is mature
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but the API is still changing and the SPARQL support is under
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active development. See the <a href="TODO.html">todo list</a>
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for the current state information.
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A summary of the changes can be found in the
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<a href="NEWS.html">NEWS</a> file,
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detailed API changes in the <a href="RELEASE.html">release notes</a>
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and file-by-file changes in the CVS <a href="ChangeLog">ChangeLog</a>.</p>
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<p>Rasqal provides:</p>
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<ul>
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<li>An RDF <a href="docs/api/query.html">query</a> construction and access API.</li>
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<li>A query execution engine including constraint expression evaluation.</li>
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<li>A query result binding API.</li>
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<li>Query language support for <a href="http://www.w3.org/TR/2007/PR-rdf-sparql-query-20071112/">SPARQL</a>.</li>
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<li>Query language support for <a href="http://www.w3.org/Submission/2004/SUBM-RDQL-20040109/">RDQL</a>.</li>
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<li>Triple store querying APIs to support running over external RDF graphs.</li>
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<li>No memory leaks.</li>
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<li><a href="roqet.html">roqet</a> standalone RDF query utility program</li>
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</ul>
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<p>Rasqal does not provide an RDF API or triple store, but relies on
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external libraries implementing the triple store API providing
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matched RDF data originally from a specified content URI. Rasqal
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ships with triple store implementations using the output of an RDF
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parser from
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<a href="http://librdf.org/raptor/">Raptor</a>
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and over a
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<a href="http://librdf.org/">Redland</a>
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indexed triple store. These can be called using the standalone
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<a href="roqet.html">roqet</a>
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query utility giving a query language
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identifier and query string to run the query over content
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described inside the query string (in RDQL, the <code>FROM</code> clause).
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</p>
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<p>Rasqal also works inside Redland (0.9.17 or newer) to provide
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support for query languages, a query API and a result bindings API
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over graphs stored in Redland.
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</p>
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<h2>Supported Query Languages</h2>
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<h3>SPARQL Query Language for RDF</h3>
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<p>Rasqal provides support for the W3C SPARQL Query Language
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being developed by the W3C
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<a href="http://www.w3.org/2001/sw/DataAccess/">RDF Data Access Working Group</a>,
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as defined in
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<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.
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It currently implements most of the functionality except for
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<code>GRAPH</code>, <code>UNION</code> and part of <code>OPTIONAL</code>.
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For detailed information on the implementation state, see the Rasqal
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<a href="TODO.html#sparql">todo / bugs list</a>
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and the <a href="http://bugs.librdf.org/">Redland issue tracker</a>.</p>
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<h3>RDF Data Query Language (RDQL)</h3>
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<p>Rasqal provides a complete implementation of the RDQL language, as defined in
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<a href="http://www.w3.org/Submission/2004/SUBM-RDQL-20040109/">RDQL - A Query Language for RDF</a>,
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W3C Member Submission 9 January 2004
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based on the earlier versions in Jena defined in
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<a href="http://www.hpl.hp.com/semweb/rdql.htm">RDQL RDF Data Query Language</a>
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and the
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<a href="http://www.hpl.hp.com/semweb/rdql-grammar.html">RDQL Grammar</a>.
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The
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<a href="http://www.hpl.hp.com/semweb/doc/tutorial/RDQL/">Jena RDQL Tutorial</a>
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gives an introduction on the language.
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Rasqal currently passes all the
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<a href="http://jena.hpl.hp.com/2003/07/query/">Jena RDQL test suite</a>
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bar a couple.
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Detail of the status of the RDQL support is given in the
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<a href="http://bugs.librdf.org/">Redland issue tracker</a>.</p>
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<h3>LAQRS Adds to Querying RDF in SPARQL (LAQRS)</h3>
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<p>
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<a href="http://www.dajobe.org/2007/04/laqrs/">LAQRS</a>
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is an <b>experimental</b> set of syntax extensions for SPARQL. The
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syntax and features may change at any time. At present Rasqal
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provides only parsing and API support for it.
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</p>
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<h2>Installation and Documentation</h2>
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<p>The public API is described in the
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<a href="librasqal.html">librasqal.3</a> UNIX manual page
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and in more detail in the
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<a href="docs/api/index.html">API reference</a>.
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It is demonstrated in the
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<a href="roqet.html">roqet</a>
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utility program which shows how to call the query engine and
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operate over the query results. When Rasqal is used inside
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<a href="http://librdf.org/">Redland</a>,
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the Redland documentation explains
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how to call the query engine and contains several example programs.
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</p>
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<p>To install Rasqal see the <a href="INSTALL.html">Installation document</a>.
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</p>
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<h2>Sources</h2>
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<p>The packaged sources are available from
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<a href="http://download.librdf.org/source/">http://download.librdf.org/source/</a> (master site) and also from the
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<a href="http://sourceforge.net/projects/librdf/">SourceForge site</a>.
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The development Subversion sources can also be
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<a href="http://svn.librdf.org/view/rasqal/">browsed with ViewCV</a>.
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</p>
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<p>Rasqal requires <a href="http://librdf.org/raptor/">Raptor</a> 1.4.0
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or newer to build and run, which can be downloaded from the same area
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as the Rasqal source and binaries.</p>
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<h2>License</h2>
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<p>This library is free software / open source software released
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under the LGPL (GPL) or Apache 2.0 licenses. See
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<a href="LICENSE.html">LICENSE.html</a> for full details.</p>
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<h2>Mailing Lists</h2>
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<p>The
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<a href="http://librdf.org/lists/">Redland mailing lists</a>
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discusses the development and use of Rasqal and Redland as well as
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future plans and announcement of releases.</p>
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<hr />
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<p>Copyright (C) 2003-2008 <a href="http://www.dajobe.org/">Dave Beckett</a><br />Copyright (C) 2003-2005 <a href="http://www.bristol.ac.uk/">University of Bristol</a></p>
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</body>
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</html>
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