SQLite
From MoodleDocs
SQLite is a serverless SQL database implementation. Moodle has experimental support for it. It is not recommended for production Moodle sites.
Configuring Moodle for SQLite
No configuration is required. Simply set $CFG->dbtype in config.php to 'sqlite'. The other database parameters are not used. The database tables are stored in the 'moodledata' file area.