The build
method signature is different for has_one
and has_many
associations.
class User < ActiveRecord::Base
has_one :profile
has_many :messages
end
The build syntax for has_many
association:
user.messages.build
The build syntax for has_one
association:
user.build_profile # this will work
user.profile.build # this will throw error
Read the has_one
association documentation for more details.