What is ontology?

An ontology is a formal system for modeling concepts and their relationships. Unlike relational database systems, which are essentially interconnected tables, ontologies put a premium on the relationships between concepts by storing the information in a graph database, or triplestore.

(The following examples use data derived from PLOS , which makes all of its Open Access data and content available.)

Relational databases are good at representing tabular data for one-to-one relationships:

Figure 1: Data with one-to-one relationships is easily represented in tabular form

However, real-life data is seldom this tidy; many-to-one and one-to-many relationships abound, which require additional tables and key-value pairs to represent data.…