Db2triples : une implémentation de R2RML et DirectMapping en Open Source. R2RML: RDB to RDF Mapping Language. This document describes R2RML, a language for expressing customized mappings from relational databases to RDF datasets.
Such mappings provide the ability to view existing relational data in the RDF data model, expressed in a structure and target vocabulary of the mapping author's choice. R2RML mappings are themselves RDF graphs and written down in Turtle syntax. R2RML enables different types of mapping implementations. Processors could, for example, offer a virtual SPARQL endpoint over the mapped relational data, or generate RDF dumps, or offer a Linked Data interface. 1 Introduction. A Direct Mapping of Relational Data to RDF.
1 Introduction Relational databases proliferate both because of their efficiency and their precise definitions, allowing for tools like SQL [SQLFN] to manipulate and examine the contents predictably and efficiently.
Resource Description Framework (RDF) [RDF-concepts] is a data format based on a web-scalable architecture for identification and interpretation of terms. This document defines a mapping from relational representation to an RDF representation. Strategies for mapping relational data to RDF abound. The direct mapping defines a simple transformation, providing a basis for defining and comparing more intricate transformations.
This specification has a companion, the R2RML mapping language [R2RML], that allows the creation of customized mapping from relational data to RDF. 2 Direct Mapping Description (Informative) The direct mapping defines an RDF Graph [RDF-concepts] representation of the data in a relational database. 2.1 Direct Mapping Example @base < . @base < . Getting started with RDFa: Creating a basic FOAF profile. Web Sémantique:RDF. Resource Description Framework. Un article de Wikipédia, l'encyclopédie libre.
Pour les articles homonymes, voir RDF. En annotant des documents non structurés et en servant d'interface pour des applications et des documents structurés (par exemple bases de données, GED, etc.) RDF permet une certaine interopérabilité entre des applications échangeant de l'information non formalisée et non structurée sur le Web. Principes fondamentaux[modifier | modifier le code] Un document structuré en RDF est un ensemble de triplets. Un triplet RDF est une association : (sujet, prédicat, objet) Le sujet, et l'objet dans le cas où c'est une ressource, peuvent être identifiés par une URI ou être des nœuds anonymes. Les documents RDF peuvent être écrits en différentes syntaxes, y compris en XML. Un document RDF ainsi formé correspond à un multigraphe orienté étiqueté. {sujet, objet, prédicat} ⇔ prédicat(objet, sujet) ce qui est équivalent à : ∃ objet, ∃ sujet tq prédicat(objet, sujet) Vocabulaires RDF[modifier | modifier le code] L'objet est :
RDF - Semantic Web Standards. Overview RDF is a standard model for data interchange on the Web.
RDF has features that facilitate data merging even if the underlying schemas differ, and it specifically supports the evolution of schemas over time without requiring all the data consumers to be changed. RDF extends the linking structure of the Web to use URIs to name the relationship between things as well as the two ends of the link (this is usually referred to as a “triple”). Using this simple model, it allows structured and semi-structured data to be mixed, exposed, and shared across different applications. This linking structure forms a directed, labeled graph, where the edges represent the named link between two resources, represented by the graph nodes.
Recommended Reading The RDF 1.1 specification consists of a suite of W3C Recommendations and Working Group Notes, published in 2014. A number of textbooks have been published on RDF and on Semantic Web in general. Discussions on a possible next version of RDF. The Friend of a Friend (FOAF) project. FOAF Vocabulary Specification. Classes Class: foaf:Agent Agent - An agent (eg. person, group, software or physical artifact).
The Agent class is the class of agents; things that do stuff. A well known sub-class is Person, representing people.