Data Modeling for Data Engineering

In this chapter, we will introduce what a data model is and why we need data modeling.

At the base of a relational database, there is the Entity-Relationship (E-R) model. Therefore, you will learn how you can use E-R models to represent data models that describe the data you have or want to collect.

We will present the E-R notation, cardinality, optionality, and the different levels of abstraction and of keys that you can have in a data model, and we will introduce two different notations commonly used in the industry, throughout the different examples that we will discuss.

We will explain a few special use cases of data models, such as weak entities or hierarchical relations, discussing their peculiarities or how they are usually implemented.

We will also introduce you to some common problems that you will face with your data, how to avoid them if possible, and how to recognize them if you cannot avoid them.

By the end of the chapter...