Question

I’m working on a Rails app where Users can have multiple roles, e.g. Manager, Employee, Admin, etc.

STI doesn’t work in this situation, due to multiple roles, but I’d still like to keep role-related data in different tables if at all possible.

So for right now, my schema looks something like this:

create_table :roles do |t|
  t.string   :name
  t.timestamps
end

create_table :users do |t|
  t.string :first_name
  t.string :last_name
  t.string :email, :default => "", :null => false
  t.timestamps
end

create_table :roles_users, :id => false do |t|
  t.references :role, :user
end

And my User/Role models both have has_and_belongs_to_many relationships with each other.

So if, for example, I need the Manager to have_many Employees, is that possible with this setup? Is it possible for a User with the Manager role to have a Manager-specific attribute like secret_manager_information? Or do I need to re-think my approach?

Answer 1

Seeing as how Managers need to keep track of Employees (and in general other roles may need to keep track of other special data), I’d say that each role is different enough that they should get their own tables (assuming that you don’t have too many roles).

For example, I would create a Manager and an Employee model:

class Manager
    attr_accessible :user_id
    has_many :employees
end

class Employee
    attr_accessible :user_id, :manager_id
    belongs_to :manager
end

Any user that is a Manager will have a record in the Manager table with user_id = user.id.
Any user that is an Employee will have a record in the Employee table with user_id = user.id and manager_id = (the id of the corresponding manager record)