5.6 Summary

The original relation model was developed by E. F. Codd three decades ago. The main idea of the model is that all data is stored in tables that are related to each other.

The object-oriented model adds various additional features such as inheritance to the relational concept.

In order to build flexible and easy-to-understand database models, many different approaches can be used. One way is to use normalization as proposed by Codd's theory. Normalization is used to avoid redundancies, to make your model more flexible and easier to understand.