MySQL How to design a database of curriculum

My question

Beginner database, do not understand design, solve.
Select Department "professional" class "return to Curriculum
How the tables should be designed.
How do I get back to the curriculum and finally generate a week?

Now I designed it.

system table (ID, name of the system)
Professional table (Professional ID, professional name, Department ID)
Class table (class ID, class name, professional ID)
Timetable (table ID, course name, class ID)

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My question

Beginner database, do not understand design, solve.
Select Department "professional" class "return to Curriculum
How the tables should be designed.
How do I get back to the curriculum and finally generate a week?

Now I designed it.

system table (ID, name of the system)
Professional table (Professional ID, professional name, Department ID)
Class table (class ID, class name, professional ID)
Timetable (table ID, course name, class ID)

If it was me, I would have built the relational table separately, storing all kinds of IDs to represent the corresponding relationships;
Each table that represents a thing contains only properties related to that thing

system table (ID, name of the system)
Professional table (Professional ID, professional name)
Class table (class ID, class name)
Timetable (table ID, course name)
Relationship table (relationship ID, System ID, professional ID, Class ID, table ID)

This helps maintain, and logic is clearer

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