Summary

In this chapter, we have learned how to manage all types of associations supported by the Doctrine ORM. We learned about unidirectional and bidirectional associations and the concept of owning side and inverse side. We also used what we have learned in previous chapters, especially the EntityManager class, the fixture loader, and generators.

In the next chapter, we will learn how to create complex queries with DQL and Query Builder.

Thanks to them, we will create lists of posts grouped by their tags. We will also take a look at the aggregate functions.