NAME¶

RDF::Trine::Model - Model class

VERSION¶

This document describes RDF::Trine::Model version 1.000

METHODS¶

"new ( $store )"

Returns a new model over the supplied rdf store or a new temporary model. If you provide an unblessed value, it will be used to create a new rdf store.

"temporary_model"

Returns a new temporary (non-persistent) model.

"dataset_model ( default => \@dgraphs, named => \@ngraphs )"

Returns a new model object with the default graph mapped to the union of the graphs named in @dgraphs, and with available named graphs named in @ngraphs.

"begin_bulk_ops"

Provides a hint to the backend that many update operations are about to occur. The backend may use this hint to, for example, aggregate many operations into a single operation, or delay index maintenence. After the update operations have been executed, "end_bulk_ops" should be called to ensure the updates are committed to the backend.

"end_bulk_ops"

Provides a hint to the backend that a set of bulk operations have been completed and may be committed to the backend.

"add_statement ( $statement [, $context] )"

Adds the specified $statement to the rdf store.

"add_hashref ( $hashref [, $context] )"

Add triples represented in an RDF/JSON-like manner to the model.

 

See "as_hashref" for full documentation of the hashref format.

"add_iterator ( $iter )"

Add triples from the statement iteratorto the model.

"add_list ( @elements )"

Adds an rdf:List to the model with the given elements. Returns the node object that is the head of the list.

"get_list ( $head )"

Returns a list of nodes that are elements of the rdf:List represented by the supplied head node.

"remove_list ( $head [, orphan_check => 1] )"

Removes the nodes of type rdf:List that make up the list. Optionally checks each node before removal to make sure that it is not used in any other statements. Returns false if the list was removed completely; returns the first remaining node if the removal was abandoned because of an orphan check.

"get_sequence ( $seq )"

Returns a list of nodes that are elements of the rdf:Seq sequence.

"remove_statement ( $statement [, $context])"

Removes the specified $statement from the rdf store.

"remove_statements ( $subject, $predicate, $object [, $context] )"

Removes all statements matching the supplied $statement pattern from the rdf store.

"size"

Returns the number of statements in the model.

"etag"

If the model is based on a store that has the capability and knowledge to support caching, this method returns a persistent token that will remain consistent as long as the store's data doesn't change. This token is acceptable for use as an HTTP ETag.

"supports ( [ $feature ] )"

If $feature is specified, returns true if the feature is supported by the underlying store, false otherwise. If $feature is not specified, returns a list of supported features.

"count_statements ( $subject, $predicate, $object )"

Returns a count of all the statements matching the specified subject, predicate and objects. Any of the arguments may be undef to match any value.

"get_statements ($subject, $predicate, $object [, $context] )"

Returns an iterator of all statements matching the specified subject, predicate and objects from the rdf store. Any of the arguments may be undef to match any value.

 

If three or fewer arguments are given, the statements returned will be matched based on triple semantics (the graph union of triples from all the named graphs). If four arguments are given (even if $context is undef), statements will be matched based on quad semantics (the union of all quads in the underlying store).

"get_pattern ( $bgp [, $context] [, %args ] )"

Returns a stream object of all bindings matching the specified graph pattern.

 

If $context is given, restricts BGP matching to only quads with the $context value.

 

%args may contain an 'orderby' key-value pair to request a specific ordering based on variable name. The value for the 'orderby' key should be an ARRAY reference containing variable name and direction ('ASC' or 'DESC') tuples. A valid %args hash, therefore, might look like "orderby => [qw(name ASC)]" (corresponding to a SPARQL-like request to 'ORDER BY ASC(?name)').

"get_sparql ( $sparql )"

Returns a stream object of all bindings matching the specified graph pattern.

"get_contexts"

Returns an iterator containing the nodes representing the named graphs in the model.

"as_stream"

Returns an iterator containing every statement in the model.

"as_hashref"

Returns a hashref representing the model in an RDF/JSON-like manner.

 

A graph like this (in Turtle):

 

  @prefix ex: <http://example.com/> .
  
  ex:subject1
    ex:predicate1
      "Foo"@en ,
      "Bar"^^ex:datatype1 .
  
  _:bnode1
    ex:predicate2
      ex:object2 ;
    ex:predicate3 ;
      _:bnode3 .
    

 

Is represented like this as a hashref:

 

  {
    "http://example.com/subject1" => {
      "http://example.com/predicate1" => [
        { 'type'=>'literal', 'value'=>"Foo", 'lang'=>"en" },
        { 'type'=>'literal', 'value'=>"Bar", 'datatype'=>"http://example.com/datatype1" },
      ],
    },
    "_:bnode1" => {
      "http://example.com/predicate2" => [
        { 'type'=>'uri', 'value'=>"http://example.com/object2" },
      ],
      "http://example.com/predicate2" => [
        { 'type'=>'bnode', 'value'=>"_:bnode3" },
      ],
    },
  }
    

 

Note that the type of subjects (resource or blank node) is indicated entirely by the convention of starting blank nodes with "_:".

 

This hashref structure is compatible with RDF/JSON and with the ARC2 library for PHP.

"as_graphviz"

Returns a GraphViz object of the RDF graph of this model, ignoring graph names/contexts.

 

This method will attempt to load the GraphViz module at runtime and will fail if the module is unavailable.

Node-Centric Graph API¶

"subjects ( $predicate, $object )"

Returns a list of the nodes that appear as the subject of statements with the specified $predicate and $object. Either of the two arguments may be undef to signify a wildcard.

"predicates ( $subject, $object )"

Returns a list of the nodes that appear as the predicate of statements with the specified $subject and $object. Either of the two arguments may be undef to signify a wildcard.

"objects ( $subject, $predicate [, $graph ] [, %options ] )"

Returns a list of the nodes that appear as the object of statements with the specified $subject and $predicate. Either of the two arguments may be undef to signify a wildcard. You can further filter objects using the %options argument. Keys in %options indicate the restriction type and may be 'type', 'language', or 'datatype'. The value of the 'type' key may be one of 'node', 'nil', 'blank', 'resource', 'literal', or 'variable'. The use of either 'language' or 'datatype' restrict objects to literal nodes with a specific language or datatype value, respectively.

"objects_for_predicate_list ( $subject, @predicates )"

Given the RDF::Trine::Node objects $subject and @predicates, finds all matching triples in the model with the specified subject and any of the given predicates, and returns a list of object values (in the partial order given by the ordering of @predicates).

"bounded_description ( $node )"

Returns an RDF::Trine::Iterator::Graph object over the bounded description triples for $node (all triples resulting from a graph traversal starting with "node" and stopping at non-blank nodes).

"as_string"

BUGS¶

Please report any bugs or feature requests to through the GitHub web interface at <https://github.com/kasei/perlrdf/issues>.

AUTHOR¶

Gregory Todd Williams "<gwilliams@cpan.org>"

COPYRIGHT¶

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.