Introduction

Object-oriented programming is a powerful concept that offers a large set of tools. But just like any tool, you need to learn how to use it properly. How you use the tools will influence the different directions you take when you build an app.

In this module, you’ll learn about the guidelines and practices that help you choose the right direction to take when you are defining your models, designing your objects or trying to write code that will be easy to understand and maintain by other people.

In the first lesson, you’ll learn how Composition and Aggregation differ when it comes to defining your data models and how they affect the rest of the app you’re building. You’ll also create the base data model for a basic contacts app, which you’ll continue building throughout the rest of the module.

But before you get into the code, you need to understand what those words mean.