Turtle (syntax)

Terse RDF Triple Language (Turtle) is a syntax and file format for expressing data in the Resource Description Framework (RDF) data model. Turtle syntax is similar to that of SPARQL, an RDF query language.

RDF represents information using semantic triples, which comprise a subject, predicate, and object. Each item in the triple is expressed as a Web URI. Turtle provides a way to group three URIs to make a triple, and provides ways to abbreviate such information, for example by factoring out common portions of URIs. For example:

 <http://example.org/person/Mark_Twain>
    <http://example.org/relation/author>
    <http://example.org/books/Huckleberry_Finn> .

History

Turtle was defined by Dave Beckett as a subset of Tim Berners-Lee and Dan Connolly's Notation3 (N3) language, and a superset of the minimal N-Triples format. Unlike full N3, which has an expressive power that goes much beyond RDF, Turtle can only serialize valid RDF graphs. Turtle is an alternative to RDF/XML, the originally unique syntax and standard for writing RDF. As opposed to RDF/XML, Turtle does not rely on XML and is generally recognized as being more readable and easier to edit manually than its XML counterpart.

SPARQL, the query language for RDF, uses a syntax similar to Turtle for expressing query patterns.

In 2011, a working group of the World Wide Web Consortium (W3C) started working on an updated version of RDF, with the intention of publishing it along with a standardised version of Turtle. This Turtle specification was published as a W3C recommendation on 25 February 2014.^[1]

A significant proportion of RDF toolkits include Turtle parsing and serializing capability. Some examples of such toolkits are Redland, Sesame, Jena and RDFLib.

Example

The following example defines 3 prefixes ("rdf", "dc", and "ex"), and uses them in expressing a statement about the editorship of the RDF/XML document:

 @prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
 @prefix dc: <http://purl.org/dc/elements/1.1/> .
 @prefix ex: <http://example.org/stuff/1.0/> .
 
 <http://www.w3.org/TR/rdf-syntax-grammar>
   dc:title "RDF/XML Syntax Specification (Revised)" ;
   ex:editor [
     ex:fullname "Dave Beckett";
     ex:homePage <http://purl.org/net/dajobe/>
   ] .

(Turtle examples are also valid Notation3).

The example encodes an RDF graph made of four triples, which express these facts:

• The W3C technical report on RDF syntax and grammar has the title RDF/XML Syntax Specification (Revised).
• That report's editor is a certain individual, who in turn
  • Has full name Dave Beckett.
  • Has a home page at a certain place.

Here are the triples made explicit in N-Triples notation:

 <http://www.w3.org/TR/rdf-syntax-grammar> <http://purl.org/dc/elements/1.1/title> "RDF/XML Syntax Specification (Revised)" .
 <http://www.w3.org/TR/rdf-syntax-grammar> <http://example.org/stuff/1.0/editor> _:bnode .
 _:bnode <http://example.org/stuff/1.0/fullname> "Dave Beckett" .
 _:bnode <http://example.org/stuff/1.0/homePage> <http://purl.org/net/dajobe/> .

The MIME type of Turtle is text/turtle. The character encoding of Turtle content is always UTF-8.^[2]

Named graphs

TriG RDF syntax extends Turtle with support for named graphs.

See also

• N-Triples
• Notation3 (N3)

References

External links

• Turtle Specification