Resource Description Framework
Resource Description Framework (RDF) provides a model for describing resources. It is the language we use to intelligently link information across different platforms.
The application and use of the RDF data model can be illustrated by the following examples:
"The author of the book is Frank"
"Frank is the author of the book"
To humans, these statements convey the same meaning (that is, that Frank is the author of a particular book). To a machine, however, these are completely different strings. Whereas humans are extremely adept at extracting meaning from differing syntactic constructs, machines remain somewhat inept. Using a triadic model of resources, property types and corresponding values, RDF attempts to provide an unambiguous method of expressing semantics in a machine-readable encoding.
RDF provides a mechanism for associating properties with resources. So, before anything about the book can be said, the data model requires the declaration of a resource representing the book. Thus, the data model corresponding to the statement "the author of the book is Frank" has a single resource book, a property-type of author and a corresponding value of Frank.
The underlying structure of any expression in RDF is a collection of triples, each consisting of a subject, a predicate and an object. A set of such triples is called an RDF graph. The term semantic technologies derives from this as in spoken language the subject is the "who" or "what" of the sentence, the predicate is the verb, and the object is any noun or concept that is part of the action of the subject.
Triples are important to specify relationships between keywords, and allows computers to link information across the World Wide Web. For example, think of a simple fact expressed as a triple: (“John Steinbeck”)(“wrote”)(“East of Eden”). In addition to expressing relationships as triples, linked data also employs common vocabularies for specific terms, so that “John Steinbeck” would be identified as the name of a person, and “East of Eden” would be identified as the name of a book.
As you can see in the image below, one triple may connect or be part of another triple extending the inference and connectivity of any part of the triple.