We already have a data source from PHP for Beginners Part 1 and PHP for Beginners Part 2 that makes our application dynamic. It reads and displays pet data, which happens to be stored in a file called pets.json. If we change something in this file, the site updates automatically. For a more complex site, however, we'll need to read and write a lot of data. So we're going to dive into the world of databases now and learn how to manage more data. This first tutorial covers database basics and how to connect and communicate with a MySQL database.