Pro Drupal 7 Development, Third Edition

Chapter 5. Working with Databases

Drupal depends on a database to function correctly. Content, comments, taxonomy, menus, users, roles, permissions, and just about everything else are stored in a database and used by Drupal as the source of information required to render content on your site and control who has access to what. Inside Drupal, a lightweight database abstraction layer exists between your code and the database. This abstraction layer removes a vast majority of the complexities of interacting with a database, and it shields Drupal from the differences between database engines. In this chapter, you'll learn about how the database abstraction layer works and how to use it. You'll see how queries can be modified by modules. Then, you'll ...