postgresql - Django- Structuring Data Tables -

i want build app using django not sure best way structure data tables be. basically, site teachers can create class , within class, create assignments. students can join class , complete assignments. thus, need keep track of teacher_users, student_users, courses, assignments, , submissions. thus, question how should structure data tables? better have 5 tables listed , lump everyone's data , sort , search every time need piece of info or better create new set of tables each teacher signs up?

i have heard bad create new tables @ runtime seems having separate tables each teacher prevent lot of sorting , searching. or there third way missing? thanks.

edit: clarify, better have 5 tables hold of data or create 1 master teacher_users , courses table , create new set of tables each teacher (when johndoe creates course, create johndoe_students table, johndoe_assignments table, , johndoe_submissions table hold course specific data.