We will cover MySQL.
The MySQL webpage provides
SQLite is another popular database engine.
The SQLite webpage provides a succinct description of the SQLite database engine. It also provides a webpage of more documentation.
Books about SQL and databases:
MySQL Community Server can be downloaded at no charge.... however, it is much easier to use Purdue's MySQL engine, since it is already installed, and each student in the course already has an account there.
SQLite can be downloaded at no charge.