There are three fields in the courses table that the UI marks as required:

- department
- course number
- course name

However, the corresponding columns in all three of these tables are nullable.  If these must be required for reasons of business logic, the columns should be not null.

Of course, it's not quite clear if all three of these columns are actually required.  Making course name required makes sense, but I'm not sure if making the department and course number required is baking in an assumption about how all academic institutions organize their course lists.