Definition

An RDF resource is any person, place, event, object (i.e. anything) that can be uniquely identified by using a Uniform Resource Identifier (URI). 

Examples

Data concerning:

  1. A store

  2. An item in a store

  3. The price of an item in a store

  4. Someone’s opinion about the price of an item in a store

  5. and so on...

In Callimachus the domain, folder path plus resource name combine to form the absolute identifier of the resource.

Adding meaning by using vocabularies

When naming resources developers are encouraged to use terms from commonly used controlled vocabularies or "ontologies".  Controlled vocabularies make it possible to construct queries that relate otherwise disparate datasets.

Commonly used vocabularies

Below are some widely used vocabularies for naming and describing resources.

Vocabulary  Description Searchable QNames
Dublin Core Fifteen properties frequently used to describe resources, similar to the type of information found on a library card.
Friend of a Friend (FOAF) A vocabulary for linking people and information about them.
Freebase A repository of open data containing almost 23 million entities.
GoodRelations A vocabulary for describing products and services.
GeoNames A vocabulary with the official geographical names for all countries and containing over eight million placenames.
Open Graph Protocol A vocabulary for describing "rich objects" in a Facebook social graph.
RDF Schema (RDFS) A vocabulary for structuring RDF resources.
Semantically-Interlinked Online Communities (SIOC) A vocabulary for linking online communities.
Simple Knowledge Organization System (SKOS) A vocabulary for organizing knowledge contained in thesauri, classification schemes, subject heading lists and taxonomies.
Vcard A vocabulary for the type of information that might be found on a business card.

Note: QName stands for "qualified name" and enables the abbreviation of URIs. The QNames shown here are used to lookup resources  in Callimachus.