的Rails 3.2的has_many：通過如何讓只有在相關的模型加入模型

Question

毫無疑問，這是一個簡單的問題，但我不能抱怨

class Service < ActiveRecord::Base 
    has_many :offers 
    has_many :offices,:through=> :offers 
    has_many :addresses,:through => :offices 
    has_many :locations,:through => :adreesses,:include => :offices 
end 

class Offer < ActiveRecord::Base 
    belongs_to :service 
    belongs_to :office 
end 

class Office < ActiveRecord::Base 
    has_many :offers 
    has_many :services,:through => :offers 
    has_one :adreess 
end 

class Address 
    belongs_to :office 
    belongs_to :location 
end 

class Location < ActiveRecord::Base 
    has_many :addressess 
    has_many :offices,:through => :addresses,:uniq=>true 
end 

我想顯示，例如：

Service name: Entrega especial 

    Location name: Distrito Capital 
    Offices: 
     Name: San Martin 

    Location name: Carabobo 
    Offices: 
     Name: San diego 

但是當我這樣做

service = Service.where(:nombre=> "Entrega especial") 
locations = service.locations 

locations.offices.each do |o| 
    puts o.nombre # only I want the offices with that service 
in that Location, no all offices in that location 
end 

我不知道如何只顯示關係辦公室，而不是所有的辦公室在該位置，即使沒有該服務的報價，在snoth方式，無需使用一個assosiation擴展和管理proxy_xxx對象

Answer 1

，也許這是最好要經過辦事處協會

@offices = service.offices.includes(:location) 

@offices.group_by(&:location).each do |location, offices_by_location| 
    puts "Location: #{location}" 
    offices_by_location.each do |office| 
    puts "Office: #{office}" 
    end 
end