what does this rails syntax mean?

Question

Ok so I built this application a while which was a rails 2.3.5 application and i used this syntax

@user = User.new
@user.build_company

and I totally forgot what this meant and how to convert to rails 3 syntax

class User < ActiveRecord::Base
  has_one :company

class Company < ActiveRecord::Base
   belongs_to :user

I vaguely remember that rails will use build_ and do something but i cant remember and I cant seem to find the documentation anywhere

Answer 1

.build_ will make a new object of the associated type (a Company) that is linked to the object it's called on (a User), but which is not yet saved. AFAIK this hasn't changed in Rails 3.

See this question: Ruby on Rails. How do I use the Active Record .build method in a :belongs to relationship?

And the docs it points to: http://api.rubyonrails.org/classes/ActiveRecord/Associations/ClassMethods.html

Answer 2

That is correct syntax for Rails 3.

has_one relationship:

@parent.build_child

has_many relationship:

@parent.children.build