RDF API for PHP

Tutorial: Using Common Vocabularies

This turorial is part of the RAP - Rdf API for PHP documentation.

RAP provides build-in support for the terms of a range of commonly known vocabularies. With version 0.9.1, RAP directly supports the following 8 vocabularies:

Vocabulary

Website

Specification

RDF

http://www.w3.org/RDF/

http://www.w3.org/RDF/#specs

RDFS

http://www.w3.org/TR/rdf-schema/

http://www.w3.org/TR/rdf-schema/

OWL

http://www.w3.org/TR/owl-ref/

http://www.w3.org/TR/owl-ref/

Dublin Core (DC)

http://dublincore.org/

http://dublincore.org/documents/dcmi-terms/
http://dublincore.org/documents/dces/

Friend of a Friend (FOAF)

http://www.foaf-project.org/

http://xmlns.com/foaf/0.1/

RSS

http://web.resource.org/rss/1.0/

http://web.resource.org/rss/1.0/spec

ATOM

http://semtext.org/atom/index.html

http://www.atomenabled.org/developers/syndication/atom-format-spec.php

VCARD

http://www.w3.org/TR/vcard-rdf

http://www.w3.org/TR/vcard-rdf#3

This tutorial describes the usage of terms from these vocabularies within RAP.

Contents:

1. Including the Necessary Vocabulary Package
2. Using the Vocabulary

1. Including the Necessary Vocabulary Package

In order to use a vocabulary you have to include the corresponding vocabulary package. The name of the file which you have to include depends on whether you are working on the RAP model layer model layer or on the RAP resource layer.

When you want to use FOAF together with a MemModel you have to include:

include( RDFAPI_INCLUDE_DIR . 'vocabulary/FOAF_C.php');

In case of working with a ResModel you have to include:

include( RDFAPI_INCLUDE_DIR . 'vocabulary/FOAF_RES.php');

The following table lists all include packages for the different vocabularies:

Vocabulary

Together with MemModel

Together with ResModel

RDF

 vocabulary/RDF_C.php vocabulary/RDF_RES.php

RDFS

 vocabulary/RDFS_C.php vocabulary/RDFS_RES.php

OWL

 vocabulary/OWL_C.php vocabulary/OWL_RES.php

Dublin Core (DC)

 vocabulary/DC_C.php vocabulary/DC_RES.php

Friend of a Friend (FOAF)

 vocabulary/FOAF_C.php vocabulary/FOAF_RES.php

RSS

 vocabulary/RSS_C.php vocabulary/RSS_RES.php

ATOM

 vocabulary/ATOM_C.php vocabulary/ATOM_RES.php

VCARD

 vocabulary/VCARD_C.php vocabulary/VCARD_RES.php

 

2. Using the Vocabulary

Now you are able to create resources for vocabulary terms by calling one simple method instead of generating them with $resouce = new Resource('uri'). To create a RDFS- comment for example you have to call:

$comment = RDFS::COMMENT();

instead of:

$comment = new Resource(http://www.w3.org/2000/01/rdf-schema#comment);

If you included the PACKAGE_VOCABULARY_CLASS package $comment is a Resource with the URI http://www.w3.org/2000/01/rdf-schema#comment. If you included the PACKAGE_VOCABULARY_RES package $comment is a ResResource with the same URI.

Normally the method to create a term is named like the term in the vocabulary using upper case. There are some reserved words in PHP like 'class' or 'list' so the methods to create these resources have other identifiers. To generate an OWL Class (http://www.w3.org/2002/07/owl#Class) for example use the method OWL::OWL_CLASS(). To find out how these methods are named have a look at the corresponding vocabulary file.

 

3. Backward Compatibility

For backward compatibility reasons, we are still supporting RAP 0.8's PACKAGE_VOCABULARY package. Including this package will create MemModel resources for all terms in all vocabularies. This is very memory consuming and should thus be avoided.

In order to use the old vocabularies you have to include:

include( RDFAPI_INCLUDE_DIR . PACKAGE_VOCABULARY);