Sources:
https://dbdiagram.io/d/5e16edf26ef5ab67de30dee1
https://docs.moodle.org/dev/Quiz_database_structure
https://docs.moodle.org/dev/Question_Engine_2
https://docs.moodle.org/dev/Question_Engine_2:Design
https://docs.moodle.org/dev/Overview_of_the_Moodle_question_engine#Database_tables