XML.com: What Is RDF

Philip Guth's personal annotations on this page

Phil_guth bookmarked on 2008-04-02 metadata rdf semanticweb xml

Most of the abstract model of RDF comes down to four simple rules:
A fact is expressed as a Subject-Predicate-Object triple, also known as a statement. It's like a little English sentence.
Subjects, predicates, and objects are given as names for entities, also called resources (dating back to RDF's application to metadata for web resources) or nodes (from graph terminology). Entities represent something, a person, website, or something more abstract like states and relations.
Names are URIs, which are global in scope, always referring to the same entity in any RDF document in which they appear.
Objects can also be given as text values, called literal values, which may or may not be typed using XML Schema datatypes.
Entities are named by Uniform Resource Identifiers (URIs), and this provides the globally unique, distributed naming system we need for distributed knowledge.
There are also other types of URIs besides http: URIs, such as URNs and TAGs, which you'll see below.
Since URIs can be quite long, in RDF notations they're usually abbreviated using the concept of namespaces from XML.
In an RDF/XML document there are two types of nodes: resource nodes and property nodes.
Notation 3 (N3), or Turtle, is another system for writing out RDF.

This link has been bookmarked by 2 people . It was first bookmarked on 01 Apr 2008, by Scott Koon.