Don't use a reference's id when creating an object - ruby-on-rails

Question

I have two objects in my app: user which has a unique parameter email_address and node which has a name and belongs to a user.
Here is my two objects in the DB, Node:
class CreateNodes < ActiveRecord::Migration
def change
create_table :nodes do |t|
t.string :name
t.references :user, index: true, foreign_key: true
t.timestamps null: false
end
end
end
And User:
class CreateUsers < ActiveRecord::Migration
def change
create_table :users do |t|
t.string :name
t.string :email_address, unique: true, index: true
t.timestamps null: false
end
end
end
My form to add a node looks like this:
<%= form_for #node do |f| %>
<%= f.text_field :name, :class => "form-control" %>
<%= f.number_field :user_id, :class => "form-control" %>
<%= f.submit 'Add the node' %>
<% end %>
However, I would like to use the user's email_address parameter instead of his/her id for convenience. I already did the changes in my controller to find the id linked to the email address but my new form returns an error, here it is:
<%= form_for #node do |f| %>
<%= f.text_field :name, :class => "form-control" %>
<%= f.email_field :user_email_address, :class => "form-control" %>
<%= f.submit 'Add the node' %>
<% end %>
The error:
undefined method `user_email_address' for #<Node id: nil, name: nil, user_id: nil>
The problem returned is clear but I don't know how to add this method and still follow the best practices for RoR development, any suggestions?

Answer 1

When you have the below line :
<%= f.email_field :user_email_address, :class => "form-control" %>
The f object, which is a Node object, calling the method user_email_address on itself. As there is no such method, you are getting the error.
Add a method inside the Node model:
def user_email_address
self.user.email_address
end
After adding the above method, below will work :
<%= f.email_field :user_email_address, :class => "form-control" %>