Billy Gray
2009-Aug-21 16:37 UTC
Getting :accepts_nested_attributes_for to work with a :belongs_to relationship
Hi Rails hackers, I just recently came across the fantastic new accepts_nested_attributes_for method off Ryans Scraps, checked out the Rails blog announcement of the feature in 2.3, watched the Rails Cast, etc. I''m trying to work it into an app where the signup form is for an Account model with a nested Owner object, which is actually a User object, hooked in via belongs_to instead of one of the has_* associations. I would think this would work using the new features, but I can''t seem to get past setting up the new form properly. I cannot find any documentation or examples out there that show the proper way to do this, so I figured I''d ask, I can''t imagine no one else is trying to do this. Here are the two models involved: class Account < ActiveRecord::Base # Relationships belongs_to :owner, :class_name => ''User'', :foreign_key => ''owner_id'' accepts_nested_attributes_for :owner has_many :users end class User < ActiveRecord::Base belongs_to :account end I have a suspicion that the fact that a user can have an account via the account :has_many users might be tripping up whatever sets up the relationship for owner (user) over the belongs_to. This is the view code in new.html.haml: - form_for :account, :url => account_path do |account| = account.text_field :name - account.fields_for :owner do |owner| = owner.text_field :name And this is the controller code for the new action: class AccountsController < ApplicationController # GET /account/new def new @account = Account.new end end When I try to load /account/new I get the following exception: NameError in Accounts#new Showing app/views/accounts/new.html.haml where line #63 raised: @account[owner] is not allowed as an instance variable name If I try to use the mysterious ''build'' method, it just bombs out in the controller: class AccountsController < ApplicationController # GET /account/new def new @account = Account.new @account.owner.build end end You have a nil object when you didn''t expect it! The error occurred while evaluating nil.build If I try to set this up using @account.owner_attributes = {} in the controller, or @account.owner = User.new, I''m back to the original error, "@account[owner] is not allowed as an instance variable name". Does anybody have the new accepts_nested_attributes_for method working with a belongs_to relationship? Many thanks for any guidance, Billy