rails association

I have following tables:

create table files ( id int auto_increment primary_key name varchar(255) )

create table users ( id int auto_increment primary_key name varchar(255) )

create table admins ( file_id int user_id int )

I would like to be able to say get the user names of the file admin. How do I create an association to 开发者_高级运维get this one

If I do has_many :admins on the files, then I can do file.admins to get the ids and to get the user names of those admins I would have to sub queries using the Find. I would like to avoid that one

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For Rails questions, rather than sharing your database create-table syntax, you should share your database migrations (just open up schema.rb and copy/paste).

It looks like you just have users, some of whom have admin privileges. The easier way of doing this is to just have a t.boolean :admin, :default => false column on your user model.

A nice benefit of this approach is that Active Record will provide you with a User#admin? method that is highly readable in conditionals and such (i.e. <%= render 'admin_menu' if @user.admin? %>).

This also sidesteps your concerns about additional queries to get the usernames after getting the listed admins.

# app/models/file.rb
class File < ActiveRecord::Base
  belongs_to :user
end

@files = File.where(:something => true).include(:user)
@files.map(&:name) #=> ['Bob', 'Cindy', ...]