PHP สอบถามแนวทางการทำ Login แบบกำหนดสิทธิ์ 3สิทธิ์ (admin, staff, user)

<?php
session_start();
include('server.php');

$errors = array();

if (isset($_POST['login_user'])) {
    $username = mysqli_real_escape_string($conn, $_POST['username']);
    $password = mysqli_real_escape_string($conn, $_POST['password']);

    if (empty($username)) {
        array_push($errors, "Username is required");
    }

    if (empty($password)) {
        array_push($errors, "Password is required");
    }

    if (count($errors) == 0) {
        $password = md5($password);
        $query = "SELECT * FROM member WHERE username = '$username' AND password = '$password' ";
        $result = mysqli_query($conn, $query);

        if (mysqli_num_rows($result) == 1) {
            $_SESSION['username'] = $username;
            $_SESSION['success'] = "Your are now logged in";
            header("location: member_main.php");
        } else {
            array_push($errors, "Wrong Username or Password");
            $_SESSION['error'] = "Wrong Username or Password!";
            header("location: login.php");
        }
    } else {
        array_push($errors, "Username & Password is required");
        $_SESSION['error'] = "Username & Password is required";
        header("location: login.php");
    }
}

Table:permissions [id,name] การเข้าถึง many to many => controls
1,'Write'
2,'Read'
3,'Edit',
4,'Delete',

Table:roles[id,name] ระบบจัดการ many to many => controls
1,'Users'
2,'Access Control Lists',
3,'Articles'

Table:controls[id,name] กลุ่มจัดการ many to many => permissions,roles && hasMany => users
1,'Root'
2,'Staff'
3,'User'

Table:control_permission[control_id,permission_id] 
1,1
1,2
1,3
1,4
2,2

Table:control_role[control_id,role_id] many to many
1,1
1,2
1,3
2,1
2,2

Table:user[id,email,control_id,password(hash)] belongsTo => control
1,[email protected],1,your password
2,[email protected],3,your password
3,[email protected],2,your password