Rails 3 default_scope sort by foreign key object name?

I'm having a little trouble figuring this out: I have a model Machine that has a foreign key on a locations table, and I want the default scope of Machine to sort by location.name开发者_JAVA技巧. Is this possible?

---

Yes, use a join to your other table.

class Machine < ActiveRecord::Base

  default_scope joins(:location).order('locations.name')

end

Make sure the relation you call in joins matches the one defined in your Machine model.

---

Yes, in your Machine model:

has_many :locations, :order => "name ASC"