Question

I’ve 2 model, User and Client with the following relationship.

• User has_many :clients
• Client belongs_to :user

How can I make all the registered users have their first :client_id => “1”, by default?

Answer 1

So, you want all new users to default to the first client. You don’t want to set a default id number, what you want to do is set it to the id of the first Client in your clients table.

So, in your users_controller#new action, all you have to do is set the client_id field to the id of the first client, like so:

class UsersController < ApplicationController

  ...

  def new
    @user = User.new(:client_id => Client.first.id)
  end

end

This makes it so that when the new User record is saved, unless the user has explicitly changed the value themselves, it will always point to the first Client record in the database.

The reason you don’t want to default it to 1 is because if you do, and you ever destroy that client from the table, then a client_id of 1 will point to a non-existent record, and your relationships will break for all new users after that happens. Even if you think that situation isn’t going to happen, it’s better to write your code in such a way that it can handle this situation, than to think it would never happen.