Overview
========

About
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`SPARQL`_ is a query language designed for the Resource Description Framework (`RDF`_).

`RDF`_ is a directed, labeled graph data format for representing information in the Web.


Features
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* It is designed to make queries from `Linked Data`_.
* It navigates the Graph Data Model of RDF.
* Can be used to express queries across diverse data sources

  * whether the data is stored natively as RDF or
  * viewed as RDF via middleware.

* Contains capabilities for querying

  * Required and optional graph patterns
  * Along with their conjunctions and disjunctions.

* Supports

  * aggregation
  * subqueries
  * negation
  * creating values by expressions
  * extensible value testing
  * and constraining queries by source RDF graph.

* Results of SPARQL queries can be result sets or RDF graphs.


.. _SPARQL: http://www.w3.org/TR/sparql11-query/
.. _Linked Data: http://www.w3.org/standards/semanticweb/data
.. _RDF: http://www.w3.org/RDF/
.. _Graph: http://en.wikipedia.org/wiki/Graph_%28mathematics%29
.. _URI: http://en.wikipedia.org/wiki/URI