I am doing a design of a database, I have built my conceptual entity-relationship model and I have arrived at the physical implementation on mysql workbench. However, I find myself having to manage users who interact with the database.
For example, a student can only view data related to his exams and not all students. To do this I thought of introducing a "login" table containing "username", "password" and "user type" to connect this table to the table that contains the student's data, I should add a "username" attribute to this table . My question, however, concerns the following question: can I add these tables in the physical schema without inserting appropriate entities in the conceptual E-R schema, or do I have to insert the "login" entity in the conceptual schema as well?