Turtle (syntax)

Terse RDF Triple Language

Filename extension	.ttl
Internet media type	text/turtle
Developed by	Dave Beckett
Type of format	Semantic Web
Container for	RDF data
Extended from	N-Triples
Standard	Specification

Turtle (Terse RDF Triple Language) is a format for expressing data in the Resource Description Framework (RDF) data model with a syntax similar to SPARQL. RDF, in turn, represents information using "triples", each of which consists of a subject, a predicate, and an object. Each of those items 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.

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.

Named Graphs

TriG RDF syntax extends Turtle with support for named graphs.

External links

• Turtle Specification

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