Student/Teacher app, both with login access

rubyonrails-talk
1

I'm trying to find the "Rails way" of modeling users of my application. Traditionally, I'd have a "users" table with common information, along with "students" and "teachers" tables. For login purposes, I'd only be concerned with the users table. (Classic class table inheritance, basically.)

Since Rails supports single table inheritance, how would the Rails gurus model this app? Is it really best to just throw everyone into one "users" table, and have a load of columns on it?

Any input will be appreciated!

2

Personally I would go with polymorphic associations. Essentially, define one table with all shared attributes (the users table) and then apply polymorphic associations to tie it with the specific teachers / students table.

http://wiki.rubyonrails.org/rails/pages/UnderstandingPolymorphicAssociations

3

I thought about that, but then wasn't crazy about:

t = Teacher.find(3) t.user.last_name

I'm not sure if you could let Teacher < User and User < ActiveRecord::Base, since you'd be applying the polymorphic to it? I apologize if this would be an easy task, I'm trying to come to the Ruby world from a history of static languages.

4

You can easily use delegates to get around this problem:

delegate :first_name, :last_name, to => :user

problem solved there. Personally I think either Polymorphic associations or even STI would suit your needs fine.

5

I hadn't thought about delegating it to the polymorphic association. My main reason for leaning away from STI is that I will likely have a good deal of columns for both Students and for Teachers that aren't applicable to the other. Additionally, storing students and teachers and in the same table just feels wrong, since they're so fundamentally different. :slight_smile:

On the plus side of STI, I can use one query and store the current_user for the request, and have access to all the applicable properties. I'm on the fence, but will read up more on Rails' polymorphic associations.