Chapter 3. Associations

In the previous chapter, we learned how to use Doctrine annotations to add mapping information to an entity class. We used code and database schema generators provided by Doctrine command-line tools, and we created a minimalist blog software that uses an EntityManager class to create, update, delete, and display blog posts.

In the third chapter, we will learn how to handle associations between entities through the following topics:

• Getting started with the Doctrine associations

• Understanding the @ManyToOne and @OneToMany annotations with the comment system

• Understanding the @ManyToMany annotation with tags