Question

I have the following two models:

class Shelf < ActiveRecord::Model
    has_many :wines

    def self.order_by_oldest_bottle_of_wine
        #TODO: order by the oldest wine bottle...
    end
end

class Wine < ActiveRecord::Model
    belongs_to :shelf

    attr_accessible :produce_date
end

In the shelf model, I want to order shelfs by the oldest wine bottle on the shelf (i.e. shelf with the oldest wine bottle first), but not 100% sure of the implementation.

Many Thanks,

Answer 1

If you are using Rails 3.x you can use any one of the following

Solution 1:

def self.order_by_oldest_bottle_of_wine
  self.wines.order("produce_date DESC")
end

Solution 2: If you want to use scope

class Wine < ActiveRecord::Model
  belongs_to :shelf
  scope :ordered_by_produce_date, order("produce_date DESC")
  attr_accessible :produce_date
end

class Shelf < ActiveRecord::Model
  has_many :wines
  def self.order_by_oldest_bottle_of_wine
    self.wines.ordered_by_produce_date
  end
end