Getting data from a database

Most applications use databases today. Be it a small website or a social network, at least some parts are powered by databases.

Yii introduces three ways to allow you to work with databases. They are as follows:

• Active Record
• Query Builder
• SQL via DAO

We will use all these methods to get data from the film, film_actor, and actor tables and show it in a list. Also, we will compare the execution time and memory usage to determine in which cases we should use these methods.

Getting ready

1. Create a new application using the Composer package manager, as described in the official guide at http://www.yiiframework.com/doc-2.0/guide-start-installation.html.
2. Download the Sakila database from http://dev.mysql.com/doc/index-other.html.
3. Execute the downloaded SQLs; first schema, then data.
4. Configure the DB connection in config/main.php to use the Sakila database.
5. Use Gii to create models for the actor and film tables.

How to do it…

1. Create app/controllers/DbController.php as follows...