Introduction to RDF

Posted Posted in Innovations, Mobile Technology, Programming

Zaptox defines RDF:

“RDF” stands for “Resource Description Framework“. It describes the exact meaning of information that represented in graph data model. Moreover, RDF signifies metadata which means data about data. The Resource Description Framework is accepted or assumed by computer. And not to  being displayed on screen.

Resource Description Framework graph
RDF Simple Graph

RDF Triples

Recourse Description Framework (RDF) model contains triples , which are based on Entity-Attribute Value model. That classifies the semantic data statement in the form of subject(entity), predicate(attribute), object(value). As well as each triple has a (URI) Uniform Resource Identifier ,that represents links in RDF graph

For Example:

Resource Description Framework triple example

RDF/XML

Keep reading, RDF scripts in XML. So, you have the knowledge about XML before you are studying RDF/XML. Basically, RDF identifies things using URIs and use property and property values to describe resources.

Additionally,

  • Resource:

In RDF, Resource is anything that have URIs, For Example;

 “http://www.zaptox.com

  • Property:

Property basically is a recourse that has name, for example; “author” or “homepage”

  • Property Value:

And Property Value describes the value of property, suppose “Iqra” or http://www.zaptox.com

Here is the code for RDF

<?xml version=”1.0”?>

<RDF>

<Description about=”http://www.zaptox.com/rdf-2″>

<author> Iqra Zaheer </author>

<homepage>http://www.zaptox.com </homepage>

</Description>

</RDF>

“Resource Description Framework” and “Semantic Web”

  • Resource Description Framework is the recommendation of World Wide Consortium.
  • Basically, RDF is the semantic web activity, so, it is more advanced technology designed to understood by the machine.
  • As well as, It is not design to displayed on web. Semantic web vision is a future technology where :
  • Website information has exact meanings.
  • Moreover, Website information can be processed and readable by computers only.
  • Machines/computer can collaborate information from website.
  • Websites has meaningful information.

RDF Schema

To define the vocabularies in RDF graph uses the language is called as RDF Schema or RDF vocabulary description language. It is extended as to indicate that we are describing specific classes and properties of resources. It is an Ontology definition language. RDF is extending is like a schema definition language in the object-oriented data models. RDF is used to represent RDF Schema.

For Example:

Resource Description Framework Schema

So, i am using RDF to provide info about Cat, Dogs, Animal

ex:Cat rdf:type rdfs:Class

ex:Animal rdf:type rdfs:Class

ex:Dogs rdf:type rdfs:Class

C rdf:type rdfs:Class

Here,

  • class C defines as triple of forms
  • rdfs:Class using predefined class
  • rdf:type using predefined property
  • class C (viewed as individual object) is an instance of predefined class
  • rdfs:Class Class name writes in uppercase letter and instance names are with lowercase letter

exthings:MyCat rdf:type ex:Animal This statement defines the individual cat and its type

Sub classes in RDF Schema

As:

ex:Cat   rdfs: subClassOf   ex:Animal

ex:Dog    rdfs:subClassOf    ex:Animal

Classes and Instances

In RDF Schema predefined property

rdfs:subClassOf  A1 in rdfs:subClassOf A2

shows that the instance of one class(A1) is the instance of another class A2

Resource Description Frame Work Schema

Property

In RDF Schema, properties can be states as it is an instance of predefined class. rdf:Property

As,

ex:author  rdf:type  rdf:Property

Property ex:author can be as predicate :

ex:ailie  ex:author  ex:book123

Domain and Range

It defines domain of property.The rdfs:domain indicates that a particular property applies to instances of class.

It defines the range of property.The rdfs:range indicates that the values of particular property are instances of class.

ex:Book  rdf:type   rdfs:Clasas

ex:Person  rdfs:type  rdfs:Class

ex:author  rdfs:domain  ex:Book

ex:author  rdfs:range   ex:Person

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