<page xmlns="http://projectmallard.org/1.0/" xmlns:its="http://www.w3.org/2005/11/its" type="topic" id="tech-tracker" xml:lang="oc">

  <info>

    <link type="guide" xref="tech" group="tracker"/>

    <credit type="author copyright">

      <name>Federico Mena Quintero</name>

      <email its:translate="no">federico@gnome.org</email>

      <years>2013</years>

    </credit>

    <include xmlns="http://www.w3.org/2001/XInclude" href="cc-by-sa-3-0.xml"/>

    <desc>Storage and retrieval for document metadata</desc>

  </info>

  <title>Tracker</title>

    Tracker is an RDF (resource data format) storage engine.  RDF consists of

    triplets such as subject:verb:object.  For example, there could be

    standard triplets for book titles and authors, such as

    Othello:has-author:William Shakespeare.  A standardized set of

    triplet forms is called an ontology.

    Tracker provides a storage for such triplets, and a query engine in the

    form of the SPARQL query language.

  
GNOME uses Tracker as a storage for document metadata. A document's

  metadata may include its title, authors, copyright, modification date, and

  keywords. All this metadata is stored as RDF triplets in Tracker, and

  queried with SPARQL by applications such as GNOME Documents. The

  <link href="http://developer.gnome.org/ontology/unstable/">ontology

  used</link> is based on various standard sub-ontologies:

  <link href="http://dublincore.org/">Dublin Core</link> for document metadata,

  and <link href="http://nepomuk.kde.org/">NEPOMUK</link> for annotations,

  files, contacts and other items.

  <list style="compact">

    <item>
<link href="https://wiki.gnome.org/Projects/Tracker">Tracker Home Page</link>
</item>

    <item>
<link href="https://wiki.gnome.org/Projects/Tracker/Documentation">Tracker documentation</link>
</item>

  </list>

</page>