A data model is an invention. It is a construct that allows us to share an understanding of how the system works. As with all good constructs, it's an abstraction; a simplification; a story.
In this course we're going to look at the Relational model, where the database is organised into tables (relationals) and each row (tuple) within that relation is coded (keyed) to allow referencing between the relationals.
The Relational model, inspite of being innovated in the 1970s is still the most popular, underpining mainstream modern databases such as Oracle 10i and MySQL 5.0
As programming languages are becoming increasingly Object orientated, programmers require a means of persistently storing their Objects. Object Orientated Databases (OODBs) exist to fulfil this purpose. OODBs may ultimately replace relational databases, but it's not clear at this stage when.