0

我是一个相当新的 Rails 开发人员，我有一个现有的应用程序，我正在尝试向（Ability）添加一个新模型，该模型与现有模型（Champion）有关联。按照我理解“has_one”和“belongs_to”机制的方式，我将它设置为对我来说在逻辑上有意义的方式，但是对于每个冠军中的每个 has_one 关系，我只能获得相同的一个记录。

这是设置：

现有模型称为 Champion，我正在创建一个新的 Ability 模型，它是 Champion 模型的一部分。我想组织 Champion 模型，使其具有 5 个能力，分别名为“q”、“w”、“e”、“r”和“passive”。每种能力只属于一个英雄。

champion_id这是我的迁移，它为 belongs_to 关联添加了一个新的 Ability 对象：

class CreateAbilities < ActiveRecord::Migration
  def change
    create_table :abilities do |t|
      t.integer :champion_id
      t.timestamps
    end
  end
end

以下是将能力引用添加到 Champion 模型的迁移：

class AddAbilitiesToChampions < ActiveRecord::Migration
  def change
    add_column :champions, :q, :integer
    add_column :champions, :w, :integer
    add_column :champions, :e, :integer
    add_column :champions, :r, :integer
    add_column :champions, :passive, :integer
  end
end

能力.rb模型：

class Ability < ActiveRecord::Base
  attr_accessible :ability_description,
                  :cost,
                  :effect,
                  :cooldown,
                  :range,
                  :name,
                  :icon,
                  :champion_id

  belongs_to :champion
end

Champion.rb 模型：

class Champion < ActiveRecord::Base
  attr_accessible :champion_id,
                  :q,
                  :w,
                  :e,
                  :r,
                  :passive

  has_one :q, :class_name => "Ability"
  has_one :w, :class_name => "Ability"
  has_one :e, :class_name => "Ability"
  has_one :r, :class_name => "Ability"
  has_one :passive, :class_name => "Ability"
end

现在，我有一个似乎可以正确创建关系的模型，但是当我在服务器上查看输出时，它为每个能力关联执行相同的选择语句，并且每次都选择相同的记录。

Started GET "/champions.json" for 127.0.0.1 at 2013-01-08 15:13:30 -0700
Processing by ChampionsController#index as JSON
  Champion Load (0.5ms)  SELECT "champions".* FROM "champions" 
  Item Load (0.4ms)  SELECT "items".* FROM "items" 
  Spell Load (0.3ms)  SELECT "spells".* FROM "spells" 
  Mastery Load (0.3ms)  SELECT "masteries".* FROM "masteries" 
  CACHE (0.0ms)  SELECT "champions".* FROM "champions" 
  Ability Load (0.6ms)  SELECT "abilities".* FROM "abilities" WHERE "abilities"."champion_id" = 1 LIMIT 1
  CACHE (0.0ms)  SELECT "abilities".* FROM "abilities" WHERE "abilities"."champion_id" = 1 LIMIT 1
  CACHE (0.0ms)  SELECT "abilities".* FROM "abilities" WHERE "abilities"."champion_id" = 1 LIMIT 1
  CACHE (0.0ms)  SELECT "abilities".* FROM "abilities" WHERE "abilities"."champion_id" = 1 LIMIT 1
  CACHE (0.0ms)  SELECT "abilities".* FROM "abilities" WHERE "abilities"."champion_id" = 1 LIMIT 1
  Ability Load (0.2ms)  SELECT "abilities".* FROM "abilities" WHERE "abilities"."champion_id" = 2 LIMIT 1
  CACHE (0.0ms)  SELECT "abilities".* FROM "abilities" WHERE "abilities"."champion_id" = 2 LIMIT 1
  CACHE (0.0ms)  SELECT "abilities".* FROM "abilities" WHERE "abilities"."champion_id" = 2 LIMIT 1
  CACHE (0.0ms)  SELECT "abilities".* FROM "abilities" WHERE "abilities"."champion_id" = 2 LIMIT 1
  CACHE (0.0ms)  SELECT "abilities".* FROM "abilities" WHERE "abilities"."champion_id" = 2 LIMIT 1
Completed 200 OK in 111ms (Views: 47.4ms | ActiveRecord: 12.8ms)

如何修改我的设置，以便 select 语句为这些属性中的每一个选择正确的能力？我已经尝试过反转关系但没有取得多大成功。任何帮助表示赞赏！

编辑：这是我的 Champions_controller.rb 中的代码，它为模型提供 JSON：

class ChampionsController < ApplicationController
  before_filter :find_champions

  def find_champions
    @champions = Champion.all
  end

  def index
    respond_to do |format|
      format.json { render :json => { "champions" => @champions }}
    end
  end
end
4

2 回答 2

1

在 Champion 模型中尝试一下。使用belongs_to，foreign_key 将在您定义关系的模型上，has_one 将在您关联的模型中查找。

belongs_to :q, :class_name => "Ability", :foreign_key => "q" 
belongs_to :w, :class_name => "Ability", :foreign_key => "w"
belongs_to :e, :class_name => "Ability", :foreign_key => "e" 
belongs_to :r, :class_name => "Ability", :foreign_key => "r"

更多信息。

于 2013-01-08T22:54:06.427 回答
0

您应该将 foreign_key 选项添加到您的冠军模型中：

has_one :q, :class_name => "Ability", :foreign_key => "q" 
has_one :w, :class_name => "Ability", :foreign_key => "w"
has_one :e, :class_name => "Ability", :foreign_key => "e" 
has_one :r, :class_name => "Ability", :foreign_key => "r"
于 2013-01-08T22:31:42.660 回答