Question

I need help to model a table structure for my database.

I have two tables: teacher and student. And to deal with authentication, I have
another table called: user. I want to maintain the information about teacher and
student separated of the information about login (user table).

For example:

     teacher
-----------------
|  id |   name  |
-----------------
| 10  |  lorem  |
| 20  |  ipsum  |
| 30  |  dolor  |
-----------------


    student
-----------------
|  id |   name  |
-----------------
|  5  |  amet   |
|  6  |  sitt   |
|  7  |  dolum  |
-----------------

Information separated in two tables.
The user table:

     user
-----------------------------------------------------------------
|  id |   teacher_id  |  student_id |    login   |   password   |
-----------------------------------------------------------------
|  1  |     10        |             |  lorem_lo  |   *******    |
|  2  |     20        |             |  ipsum_lo  |   *******    |
|  3  |     30        |             |  dolor_lo  |   *******    |
|  4  |               |     5       |  amet_lo   |   *******    |
|  5  |               |     6       |  sitt_lo   |   *******    |
|  6  |               |     7       |  dolum_lo  |   *******    |
-----------------------------------------------------------------

The solution I thought was that. I ask your opinion about.
Is that a good solution?

Thanks in advance.

P.S.: I’m using Mysql (InnoDB)

Answer 1

To eliminate empty fields from user table, you can do this:

--------------------------------------------------
|  id  |  user  |  level  |  login  |  password  |
--------------------------------------------------

where user contains all your students and teachers ID’s and level that contains 1 for teachers and 2 for students.

In this case, you can use level column to create access in your app.

Another method, is with one table… separate students and teacher trough levels but isn’t best practice.