Does moodle have a database that contain courses? Or courses have to be added manually one by one?
Yes and Yes although that's probably not what you are asking.
You can bulk create courses. See this page - Upload_courses
Thank you for your response. However what i mean is, does module have like a database that contains some random courses? Reason is I am developing a plugin for my Master's Thesis for data visualisation and i will be needing some information (courses), which will be analysed and can be visualised by students depending on the courses they have registered for (just an instance to make you understand me better). Thus i want to know if i will have to manually add courses and course information or if there is a database i can connect to for some random courses or if there is somewhere i can get them and upload them as courses in moodle.
Thanks
If you want randomly created courses and data then you can create that. See - Test_site_generator