按歸屬關系中的父項排序active_admin列

Question

我有兩個模型： show_request和show 。 一個show_Request屬於一個show ，一個show has_many show_requests 。 在active_admin的show_request頁面上，我想通過show的created_at值對show_requests進行排序。 到目前為止，這是我的代碼：

ActiveAdmin.register ShowRequest do

  controller do
    def scoped_collection
      end_of_association_chain.includes(:show)
      #I also tried ShowRequest.includes(:show)
    end
  end

  index do
    column 'Show', sortable: "shows.created_at_asc" do |show_req|
        link_to show_req.show.name, admin_show_path(show_req.show)
    end
  end

end

這是服務器日志：

Started GET "/admin/show_requests" for 127.0.0.1 at 2015-09-18 09:35:36 -0400
Processing by Admin::ShowRequestsController#index as HTML
  AdminUser Load (0.3ms)  SELECT  "admin_users".* FROM "admin_users"  WHERE "admin_users"."id" = 1  ORDER BY "admin_users"."id" ASC LIMIT 1
   (1.2ms)  SELECT COUNT(*) FROM "show_requests"  WHERE (not_going_to_show = 'f' OR i_want_my_horse_to_compete = 't')
   (0.2ms)  SELECT COUNT(*) FROM "show_requests"
   (0.2ms)  SELECT COUNT(*) FROM "show_requests"  WHERE (not_going_to_show = 't' AND i_want_my_horse_to_compete = 'f')
   (0.3ms)  SELECT COUNT(count_column) FROM (SELECT  1 AS count_column FROM "show_requests"  WHERE (not_going_to_show = 'f' OR i_want_my_horse_to_compete = 't') LIMIT 30 OFFSET 0) subquery_for_count
  CACHE (0.0ms)  SELECT COUNT(count_column) FROM (SELECT  1 AS count_column FROM "show_requests"  WHERE (not_going_to_show = 'f' OR i_want_my_horse_to_compete = 't') LIMIT 30 OFFSET 0) subquery_for_count
  CACHE (0.0ms)  SELECT COUNT(*) FROM "show_requests"  WHERE (not_going_to_show = 'f' OR i_want_my_horse_to_compete = 't')
  CACHE (0.0ms)  SELECT COUNT(count_column) FROM (SELECT  1 AS count_column FROM "show_requests"  WHERE (not_going_to_show = 'f' OR i_want_my_horse_to_compete = 't') LIMIT 30 OFFSET 0) subquery_for_count
  ShowRequest Load (2.0ms)  SELECT  "show_requests".* FROM "show_requests"  WHERE (not_going_to_show = 'f' OR i_want_my_horse_to_compete = 't')  ORDER BY "show_requests"."id" desc LIMIT 30 OFFSET 0
  Show Load (9.7ms)  SELECT "shows".* FROM "shows"  WHERE "shows"."id" IN (2, 1)
  User Load (0.4ms)  SELECT  "users".* FROM "users"  WHERE "users"."id" = $1 LIMIT 1  [["id", 2]]
  User Load (0.2ms)  SELECT  "users".* FROM "users"  WHERE "users"."id" = $1 LIMIT 1  [["id", 1]]
  CACHE (0.0ms)  SELECT  "users".* FROM "users"  WHERE "users"."id" = $1 LIMIT 1  [["id", 1]]
  Show Load (0.2ms)  SELECT "shows".* FROM "shows"
  User Load (0.2ms)  SELECT "users".* FROM "users"

這是行不通的。 它根本不影響列的順序。 我該如何解決？

Answer 1

看一下日志的這一部分：

ShowRequest Load (2.0ms)  SELECT  "show_requests".* FROM "show_requests"  WHERE (not_going_to_show = 'f' OR i_want_my_horse_to_compete = 't')  ORDER BY "show_requests"."id" desc LIMIT 30 OFFSET 0
Show Load (9.7ms)  SELECT "shows".* FROM "shows"  WHERE "shows"."id" IN (2, 1)

您可以看到ShowRequest和Show分別在不同的查詢中加載。 sortable在這里不起作用，因為沒有連接就無法按另一個表的字段對一個表進行排序。 解決方法應該是告訴ActiveRecord您需要在查詢中引用shows表：

controller do
  def scoped_collection
    super.includes(:show).references(:shows)
  end
end

index do
  column :show, sortable: 'shows.created_at'
end

references僅與includes ，並在急切加載時強制Rails執行聯接。