In this chapter, we learned the importance of databases and how to use them from our web application: from setting up the connection using PDO and creating and fetching data on demand to constructing more complex queries that fulfill our needs. With all of this, our application looks way more useful now than when it was completely static.

In the next chapter, we will discover how to apply the most important design patterns for web applications through Model View Controller (MVC). You will gain a sense of clarity in your code when you organize your application in this way.