Graphs

Metadata statements are often depicted as graphs having two nodes connected by an arc.

Although, as we saw in our example with a car, each statement has three parts and therefore is a in the form of two nodes connected by an arc, for human readability repeated nodes can be represented as a single thing:

This is called a graph. We can represent the statements from our car example with a graph that lists the car node only once:

This does not change the fact that our metadata statements about the car are separate statements that can be used independently. The graph is just a convenient way to present our data so that it is more easily understood.

As we'll see in the section on the Semantic Web, statements are the key to linking, and linking, when thought of as a graph in form, does create a true Web of Data.