Basic Ideas of RDF(2 o The fundamental concepts of rdF are resources properties statements 6 Chapter 3 A Semantic Web primer
Chapter 3 A Semantic Web Primer 6 Basic Ideas of RDF (2) ⚫ The fundamental concepts of RDF are: – resources – properties – statements
Resources e We can think of a resource as an object a thing" we want to talk about E.g. authors, books, publishers, places, people, hotels o Every resource has a uri, a Universal Resource Identifier ● A URi can be a URL (Web address)or some other kind of unique identifier 7 Chapter 3 A Semantic Web primer
Chapter 3 A Semantic Web Primer 7 Resources ⚫ We can think of a resource as an object, a “thing” we want to talk about – E.g. authors, books, publishers, places, people, hotels ⚫ Every resource has a URI, a Universal Resource Identifier ⚫ A URI can be – a URL (Web address) or – some other kind of unique identifier
Properties e Properties are a special kind of resources o They describe relations between resources E.g. written by, age, title, etc e Properties are also identified by Urls o Advantages of using URIs A global, worldwide, unique naming scheme Reduces the homonym problem of distributed data representation 8 Chapter 3 A Semantic Web primer
Chapter 3 A Semantic Web Primer 8 Properties ⚫ Properties are a special kind of resources ⚫ They describe relations between resources – E.g. “written by”, “age”, “title”, etc. ⚫ Properties are also identified by URIs ⚫ Advantages of using URIs: – Α global, worldwide, unique naming scheme – Reduces the homonym problem of distributed data representation
Statements o Statements assert the properties of resources o A statement is an object-attribute-value triple It consists of a resource, a property, and a value e Values can be resources or literals Literals are atomic values (strings) 9 Chapter 3 A Semantic Web primer
Chapter 3 A Semantic Web Primer 9 Statements ⚫ Statements assert the properties of resources ⚫ A statement is an object-attribute-value triple – It consists of a resource, a property, and a value ⚫ Values can be resources or literals – Literals are atomic values (strings)
Three views of a statement ● A triple ● A piece of a graph ● A piece of XML code Thus an rdf document can be viewed as ● A set of triples o A graph(semantic net) ● An xml document 10 Chapter 3 A Semantic Web primer
Chapter 3 A Semantic Web Primer 10 Three Views of a Statement ⚫ A triple ⚫ A piece of a graph ⚫ A piece of XML code Thus an RDF document can be viewed as: ⚫ A set of triples ⚫ A graph (semantic net) ⚫ An XML document