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RDF::Trine - An RDF Framework for Perl


This document describes RDF::Trine version 1.019


  use RDF::Trine;
  my $store = RDF::Trine::Store::Memory->new();
  my $model = RDF::Trine::Model->new($store);
  # parse some web data into the model, and print the count of resulting RDF statements
  RDF::Trine::Parser->parse_url_into_model( '', $model );
  print $model->size . " RDF statements parsed\n";
  # Create a namespace object for the foaf vocabulary
  my $foaf = RDF::Trine::Namespace->new( '' );
  # Create a node object for the FOAF name property
  my $pred = $foaf->name;
  # alternatively:
  # my $pred = RDF::Trine::Node::Resource->new('');
  # Create an iterator for all the statements in the model with foaf:name as the predicate
  my $iter = $model->get_statements(undef, $pred, undef);
  # Now print the results
  print "Names of things:\n";
  while (my $st = $iter->next) {
    my $s = $st->subject;
    my $name = $st->object;
    # $s and $name have string overloading, so will print correctly
    print "The name of $s is $name\n";


RDF::Trine provides an Resource Descriptive Framework (RDF) with an emphasis on extensibility, API stability, and the presence of a test suite. The package consists of several components:

  • RDF::Trine::Model - RDF model providing access to a triple store. This module would typically be used to access an existing store by a developer looking to "Just get stuff done."

  • RDF::Trine::Parser - RDF parsers for various serialization formats including RDF/XML, Turtle, RDFa, and RDF/JSON.

  • RDF::Trine::Store::Memory - An in-memory, non-persistant triple store. Typically used for temporary data.

  • RDF::Trine::Store::DBI - A triple store for MySQL, PostgreSQL, and SQLite, based on the relational schema used by Redland. Typically used to for large, persistent data.

  • RDF::Trine::Iterator - Iterator classes for variable bindings and RDF statements, used by RDF::Trine::Store, RDF::Trine::Model, and RDF::Query.

  • RDF::Trine::Namespace - A convenience class for easily constructing RDF::Trine::Node::Resource objects from URI namespaces.


iri ( $iri )

Returns a RDF::Trine::Node::Resource object with the given IRI value.

blank ( $id )

Returns a RDF::Trine::Node::Blank object with the given identifier.

literal ( $value, $lang, $dt )

Returns a RDF::Trine::Node::Literal object with the given value and optional language/datatype.

variable ( $name )

Returns a RDF::Trine::Node::Variable object with the given variable name.

statement ( @nodes )

Returns a RDF::Trine::Statement object with the supplied node objects.

store ( $config )

Returns a RDF::Trine::Store object based on the supplied configuration string.

default_useragent ( [ $ua ] )

Returns the LWP::UserAgent object used by default for any operation requiring network requests. Ordinarily, the calling code will obtain the default user agent, and clone it before further configuring it for a specific request, thus leaving the default object untouched.

If $ua is passed as an argument, sets the global default user agent to this object.


Please report any bugs or feature requests to through the GitHub web interface at



Gregory Todd Williams <>


Copyright (c) 2006-2012 Gregory Todd Williams. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.