Rules

There are rules to follow in RDF. When using RDF there are resources which are identified by web identifiers, Uniform Resource Identifier (URI). This URI is used to idnetify resources which can be used over a network, typically the World Wide Web (P. Champin 2005). These resources make up the a subject-predicate-object expressions, called triples in RDF terminology. The triples are also called: Resource, Property, Value (R,P,V). Resources have Properties, which are identified by URIs. Properties have Values, which can be strings or numbers or Resources (Wikipedia 2008 and The RDF.net Challenge 2003).

Explanation of (R,P,V):

• Resource can be identified by or have a URI

Example: “http://en.wikipedia.org/wiki/Resource_Description_Framework”

• Property can be identified by a Resource that has a name

Example: “homepage” or an “author”

• Value can be identified by the value of a Property

Example: “http://en.wikipedia.org/wiki/Main_Page” or “Jane Doe”

-Note: the value does not have to be the same Resource

Sample code that could describe the resource for “http://en.wikipedia.org/wiki/Resource_Description_Framework”:

 
<?xml version="1.0"?>
<RDF>
  <Description about="http://en.wikipedia.org/wiki/Resource_Description_Framework/RDF">
    <author>Jane Doe</author>
    <homepage>http://en.wikipedia.org/wiki/Main_Page>
  </Description>
</RDF> >    

The above sample syntax and explanation (W3 schools 2008). 

Additional explanation by subject-predicate-object:

-Subject denotes the Resource

-Predicate denotes traits or aspects of the Resource and expresses a relationship between the subject and the object (Wikipedia (2008).

Example:

One way to represent the notion "The sky has the color blue" in RDF is as the triple: a subject denoting "the sky", a predicate denoting "has the color", and an object denoting "blue" (Wikipedia 2008).