Ho编写一个范围来显示事件的分级- Rails 5

Question

• 我想写一个范围，列出一个事件的所有评级。
• 谁能建议我如何写一个范围，列出event = Event.find(5)的评级，它表示为:rateable_id => 5

航站楼：

2.3.0 :005 >   event = Event.find(5)
  Event Load (0.2ms)  SELECT  "events".* FROM "events" WHERE "events"."id" = ? LIMIT ?  [["id", 5], ["LIMIT", 1]]
 => #<Event id: 5, title: "Speed Social - Graduate Professionals", description: "Lorem ipsum dolor sit amet, consectetur adipiscing...", created_at: "2016-12-04 14:02:09", updated_at: "2016-12-04 14:02:09", slug: nil> 
2.3.0 :006 > 
2.3.0 :007 >   
2.3.0 :008 >   ap Rate.all
  Rate Load (0.3ms)  SELECT "rates".* FROM "rates"
[
    [0] #<Rate:0x007f84fd142380> {
                   :id => 8,
             :rater_id => 1,
        :rateable_type => "Event",
          :rateable_id => 5,
                :stars => 3.0,
            :dimension => "style",
           :created_at => Mon, 02 Jan 2017 15:00:51 UTC +00:00,
           :updated_at => Mon, 02 Jan 2017 15:00:51 UTC +00:00
    },
    [1] #<Rate:0x007f84fd142178> {
                   :id => 9,
             :rater_id => 4,
        :rateable_type => "Event",
          :rateable_id => 5,
                :stars => 2.0,
            :dimension => "style",
           :created_at => Mon, 02 Jan 2017 15:12:29 UTC +00:00,
           :updated_at => Mon, 02 Jan 2017 15:12:29 UTC +00:00
    },
    [2] #<Rate:0x007f84fd141f70> {
                   :id => 10,
             :rater_id => 1,
        :rateable_type => "Event",
          :rateable_id => 6,
                :stars => 4.0,
            :dimension => "style",
           :created_at => Mon, 02 Jan 2017 15:40:37 UTC +00:00,
           :updated_at => Mon, 02 Jan 2017 15:40:37 UTC +00:00
    }
]
 => nil 

图式

ActiveRecord::Schema.define(version: 20170102134239) do

  create_table "events", force: :cascade do |t|
    t.string   "title"
    t.text     "description"
    t.datetime "created_at",  null: false
    t.datetime "updated_at",  null: false
    t.string   "slug"
    t.index ["slug"], name: "index_events_on_slug", unique: true
  end

  create_table "events_users", id: false, force: :cascade do |t|
    t.integer "event_id", null: false
    t.integer "user_id",  null: false
  end

  create_table "overall_averages", force: :cascade do |t|
    t.string   "rateable_type"
    t.integer  "rateable_id"
    t.float    "overall_avg",   null: false
    t.datetime "created_at"
    t.datetime "updated_at"
  end

  create_table "rates", force: :cascade do |t|
    t.integer  "rater_id"
    t.string   "rateable_type"
    t.integer  "rateable_id"
    t.float    "stars",         null: false
    t.string   "dimension"
    t.datetime "created_at"
    t.datetime "updated_at"
    t.index ["rateable_id", "rateable_type"], name: "index_rates_on_rateable_id_and_rateable_type"
    t.index ["rater_id"], name: "index_rates_on_rater_id"
  end

  create_table "rating_caches", force: :cascade do |t|
    t.string   "cacheable_type"
    t.integer  "cacheable_id"
    t.float    "avg",            null: false
    t.integer  "qty",            null: false
    t.string   "dimension"
    t.datetime "created_at"
    t.datetime "updated_at"
    t.index ["cacheable_id", "cacheable_type"], name: "index_rating_caches_on_cacheable_id_and_cacheable_type"
  end

  create_table "users", force: :cascade do |t|
    t.string   "email",                  default: "", null: false
    t.string   "encrypted_password",     default: "", null: false
    t.string   "reset_password_token"
    t.datetime "reset_password_sent_at"
    t.datetime "remember_created_at"
    t.integer  "sign_in_count",          default: 0,  null: false
    t.datetime "current_sign_in_at"
    t.datetime "last_sign_in_at"
    t.string   "current_sign_in_ip"
    t.string   "last_sign_in_ip"
    t.datetime "created_at",                          null: false
    t.datetime "updated_at",                          null: false
    t.string   "firstname"
    t.string   "lastname"
    t.string   "slug"
    t.index ["email"], name: "index_users_on_email", unique: true
    t.index ["reset_password_token"], name: "index_users_on_reset_password_token", unique: true
    t.index ["slug"], name: "index_users_on_slug", unique: true
  end

end

Answer 1

若要查找给定事件的所有评等，请从Controller调用范围

rates = Rate.find_events(event_id)

和内部的rate.rb文件

scope :find_events, -> (event_id){ where(rateable_id: event_id) }