How to model users and administrators in a database? - php

Question

I'm quite new to mysql. I want to make a database in mysql for a school. This database should store teachers' information and give some of these teachers the possibilities to create groups.
So I created a database that contains a table group and a table professeur. Group has many-to-many relationship with teachers and vice-versa which derives another table Group_professeur. Here is a simple structure of the tables:
Professeur:
CREATE TABLE IF NOT EXISTS `professeur` (
`id_professeur` int(11) NOT NULL AUTO_INCREMENT,
`nom_professeur` varchar(50) NOT NULL,
`prenom_professeur` varchar(50) DEFAULT NULL,
PRIMARY KEY (`id_professeur`),
UNIQUE KEY `LOGIN` (`login`),
UNIQUE KEY `MDP` (`passwd`),
) ENGINE=InnoDB DEFAULT CHARSET=utf8 AUTO_INCREMENT=103 ;
Group
CREATE TABLE IF NOT EXISTS `groupe` (
`id_groupe` int(11) NOT NULL AUTO_INCREMENT,
`nom_groupe` varchar(255) NOT NULL,
`id_prof_responsable` int(11) NOT NULL,
PRIMARY KEY (`id_groupe`),
UNIQUE KEY `nom_groupe` (`nom_groupe`),
KEY `id_prof_responsable` (`id_prof_responsable`),
) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=1 ;
ALTER TABLE `groupe`
ADD CONSTRAINT `fk_professeur_to_groupe` FOREIGN KEY (`id_prof_responsable`) REFERENCES `professeur` (`id_professeur`) ON UPDATE CASCADE
Groupe_has_teachers:
CREATE TABLE IF NOT EXISTS `groupe_professeur` (
`id_groupe` int(11) NOT NULL,
`id_professeur` int(11) NOT NULL,
KEY `id_groupe` (`id_groupe`),
KEY `id_professeur` (`id_professeur`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
ALTER TABLE `groupe_professeur`
ADD CONSTRAINT `groupe_professeur_ibfk_2` FOREIGN KEY (`id_professeur`) REFERENCES `professeur` (`id_professeur`) ON UPDATE CASCADE,
ADD CONSTRAINT `groupe_professeur_ibfk_1` FOREIGN KEY (`id_groupe`) REFERENCES `groupe` (`id_groupe`) ON UPDATE CASCADE;
Teachers can modify only the group(s) they created(i.e they can insert and delete members from their groups). Also, not all teachers have the right to create and modify groups.
After creating the tables, I was wondering who will give them the appropriate rights to do all these stuffs. I thought about creating an administrator. The admin can give the rights to certain teachers to create and modify their own groups and can also revoke these privileges.
I created a table which will store an administrator but who will give the admin the necessary rights to do these. Which brings me back to square one. And this table might have some relationships with other tables in the database thereby deriving some unnecessary tables.
Anyway I thought about changing the professors table to something general like staffs and adding the admin to the table. And then adding these staffs to the database. That means creating a new staff corresponds to adding the staff's information to the table staffs and then adding this staff as a user to the database. From there I can use SQL functions like GRANT and REVOKE to each user.
I'm not sure if this method is very efficient because these means if the school has 1000 professors then it has 1000 users in it's database.
Is there any efficient way to tackle this problem? Thanks.

Answer 1

Controlling application user access using the built-in MySQL notion of a user is unorthodox. For a basic application, I would recommend having another column in the group table for an owner_user_id that would refer to the professor table. Then in the application code, check for that id when the group is being altered.
Good luck!

Answer 2

You'll want to take a look at Role-based Access Control
Another explanation by Tony Marston