Model,Syntax,Schema

Without trying to get too complicated, I'll spend this chapter telling you about the different RDF components. I'll finish off with a nice looking example, so please stay with me.

At the core of RDF we have the RDF Data Model for representing named properties and their values. These properties serve both to represent attributes of resources (and in this sense correspond to usual attribute-value pairs) and to represent relationships between resources. The RDF data model is a syntax-independent way of representing RDF expressions.

The RDF Syntax is for expressing and transporting this metadata in a manner that maximizes the interoperability of indepently developed web servers and clients. The syntax uses the eXtensible Markup Language (XML).

Last, but not least, RDF Schemas are a collection of information about classes of RDF nodes, including properties and relations. RDF schemas are specified using a declarative representation language influenced by ideas from knowledge represention, e.g., semantic nets, frames, and predicate logic, as well as database schema representation models such as binary relational models, and graph data models.

RDF in itself does not contain any predefined vocabularies for authoring metadata. It is though expected that standard vocabularies will emerge, after all this is a core requirement for large-scale interoperability. Anyone can design a new vocabulary, the only requirement for using it is that a designating URI is included in the metadata instances using this vocabulary.