Rails ActiveRecord多级关联

Question

I'm having a little trouble with querying multiple tables with different types of association. Can someone please point me in the right direction?

class Sale < ActiveRecord::Base
    has_many :items, :dependent => :destroy
end

class Item < ActiveRecord::Base
  belongs_to :sale, :dependent => :destroy
  has_many :images, :dependent => :destroy
end

class Image < ActiveRecord::Base
  belongs_to :item, :dependent => :destroy
end

What would be the query to get all items relating to a sale with the ID 1, and then loop through all the images relating to each item returned?

Thanks for your help.

Answer 1

You can define :through => :something in a has_many association

class Sale < ActiveRecord::Base
    has_many :items, :dependent => :destroy
    has_many :images, :through => :items
end

and then simply query

Sale.find(1).images