Databases and MySQL

In the past, Drupal has supported two databases--MySQL and PostgreSQL. Drupal 7 and 8 have moved beyond this. Drupal now uses the powerful PHP Data Objects (PDO) library that is standard in PHP 5/7. This library is an abstraction layer that allows developers to support numerous databases, including MySQL, PostgreSQL, SQLite, and MariaDB.

The minimum database versions for Drupal 8 are as follows:

• MySQL 5.5.3/MariaDB 5.5.20/Percona Server 5.5.8 or higher with PDO and an InnoDB-compatible primary storage engine
• PostgreSQL 9.1.2 or higher with PDO
• SQLite 3.7.11 or higher

Additionally, Drupal provides a powerful database API along with some SQL coding conventions that make it easy to interact with your database--both combined allow you to write safe and portable SQL. However, more and more abstractions have been made at different levels, removing the need for SQL writing almost completely. However, we will still see some examples just so your toolbox does not miss anything, as well as cover all the tools at your disposal for querying your database.