What's a RDF triple?

Question

In layman\'s terms, what\'s a RDF triple?

Answer 1

RDF is a Language, i.e., a system of signs, syntax, and semantics for encoding and decoding information (data in some context).

In RDF, a unit of observation (Data) is represented by a sentence that consists of three parts: subject, predicate, object. Basically, this is the fundamental structure of natural language speech.

The sign used to denote entities (things) participating in entity relationships represented by RDF is an IRI (which includes HTTP URIs). Each subject and predicate (and optionally, object) component of an RDF sentence is denoted by an IRI.

The syntax (grammar) is abstract (meaning it can be represented using a variety of notations) in the form of subject, predicate, and object arrangement order.

The semantics (the part overlooked most often) is all about the meaning of the subject, predicate, and object roles in an RDF statement.

When you use HTTP URIs to denote RDF statement subject, predicates, and (optionally) objects, you end up with structured data (collections of entity relationship types) that form a web -- just as you have today on the World Wide Web.

When the semantics of a predicate (in particular) in an RDF statement are both machine and human comprehensible you have a web of entity relationship types that provide powerful encoding of information that is a foundation for knowledge (inference and reasoning).

Here are examples of simple RDF statements:

{
    <#this>             a  schema:WebPage                          .
    <#this>  schema:about  dbpedia:Resource_Description_Framework  .
    <#this>  skos:related     . 
}

I've used braces to enclose the examples so that this post turns into a live RDF-based Linked Data demonstration, courtesy of relative HTTP URIs and the # based fragment identifier (indexical).

Results of the RDF statements embedded in this post, courtesy of nanotation (embedding RDF statements wherever text is accepted):

1. Basic Entity Description Page -- Each Statement is identified by a hyperlink that resolves to its description (subject, predicate, object parts)
2. Deeper Faceted Browsing Page -- Alternative view that lends itself to deeper exploration and discovery by following-your-nose through the hyperlinks that constitute the data web or web of linked data.
3. Description of an embedded statement -- About a specific RDF statement.

Here's the visualization generated from the triples embedded in this post (using our Structured Data Sniffer Browser Extension, using RDF-Turtle Notation: