SPARQL

SPARQL is a graph- based query language for RDF. The name is a recursive acronym for SPARQL Protocol And RDF Query Language.

The RDF Data Access Working Group ( DAWG ) of the World Wide Web Consortium spurred the development and standardization of SPARQL. In April 2006, SPARQL has been recognized as a Candidate Recommendation, in October 2006, however, it has again been demoted to a Working Draft. Since June 2007, SPARQL was again present as Candidate Recommendation of the W3C. January 15, 2008 SPARQL was finally released as a recommendation by the W3C. Since March 21, 2013 is the W3c Recommendation for SPARQL 1.1 published. SPARQL is the successor of several query languages ​​(eg RDF query language, RDQL ), which also access RDF data.

An example of

The request in the following example finds the names of all African capitals and the country in which is located the respective capital.

PREFIX abc:    SELECT? Capital? Country    WHERE {     ? x abc: cityname capital; ?         abc: isCapitalOf y? .     ? y abc: countryName country; ?         abc: abc isInContinent: Africa.    } Variables are identified by a prefix "? " ( Is possible alternatively "$"). As a result of the request in the above example, all variable assignments for? " Capital" and "? Country" returned that meet the four defined RDF triples.

Because the contest of URIs reduces the readability of a query prefixes can be used. Here is a "abc " for " http://example.com/exampleOntology #"

Request Engines