Glossary · Semantic web foundations

RDF (Resource Description Framework)

Also known as: Resource Description Framework, RDF graph, triples

RDF (Resource Description Framework) is the W3C standard data model for describing resources as statements of subject, predicate and object, called triples. Resources and predicates are identified by IRIs, so statements from different sources can be merged into one graph.

Semantic web
Ontology
Information architecture

In one sentence

RDF is the W3C data model of subject–predicate–object triples identified by IRIs; iiRDS metadata is written in RDF.

Example

The triple “topic 1312 — has topic type — GenericTask” states in RDF that a topic is a task.

How it applies

iiRDS: iiRDS is an RDF vocabulary. Its schema is written in RDF Schema (RDFS), and every package's metadata.rdf must be serialized in RDF 1.1 XML syntax; proprietary extensions may use only RDF and RDFS.
Technical documentation: RDF lets metadata from different systems — CCMS, PLM, ERP — be combined without a shared database schema. Two statements about the same IRI simply become part of the same graph.
Syntaxes: RDF is a model, not a file format. The same graph can be written as RDF/XML, Turtle (used in the examples of this glossary for readability) or JSON-LD.
AI and knowledge graphs: RDF graphs are the foundation of knowledge graphs. They give language models explicit, queryable facts (with SPARQL) to ground their answers in, instead of patterns in text.

RDF vs. XML

XML describes a tree of elements; its meaning depends on the schema of each document type. RDF describes a graph of statements whose meaning is fixed by the IRIs of its predicates — which is why RDF data from different sources can be merged and XML documents generally cannot.

In RDF

A single triple, in Turtle:

@prefix iirds: <http://iirds.tekom.de/iirds#> .

<https://example.com/iirds/io/1312> iirds:has-topic-type iirds:GenericTask .