PyQt5 do I understand how models and databases work correctly?

Question

Python

Hello.
I want to try to rewrite my program according to the rules of QT (model + display).
I'm trying to figure it all out. Let me know if I understand the procedure for my task correctly.
Task: Rewrite the part of the program that is responsible for the list of employees and their editing. Each worker has over 30 data columns. All this is stored in a MySQL database.
I've put together a schematic as I understand it.

Questions:
1) Is the sequence of actions correct?
2) Do I need to create 2 models (for a list of employees, and for a single employee)?
3) It turns out that every time I change one worker, I have to get the full list again and create a new model?