Rails 4-复杂模型验证（has_many，通过）

Question

我正在尝试验证我的成分模型中的 "name" 属性。但是，当我在我的 Ingredient 模型中添加 validates :name, :uniqueness => true 时，它不会验证名称（可以插入具有相同名称的成分）。成分模型与其他模型有着复杂的关系。请看下面的代码。

我的最终目标是允许用户在 Ingredient table 中不存在该成分的情况下创建该成分。如果成分已经存在，则使用成分 ID 作为数量。如果有人知道如何实现这一目标，请提供解决方案。提前致谢。

ingredient.rb

class Ingredient < ActiveRecord::Base
    has_many :quantities
    has_many :recipes, through: :quantities

    validates :name, :presence => true, :uniqueness => true
end

quantity.rb

class Quantity < ActiveRecord::Base
  belongs_to :ingredient
  belongs_to :recipe

  accepts_nested_attributes_for :ingredient,
                                :reject_if => :all_blank

  validates :ingredient, :uniqueness => true
end

recipe.rb

class Recipe < ActiveRecord::Base
    has_many :quantities,
                dependent: :destroy
    has_many :ingredients, 


                :through => :quantities

        accepts_nested_attributes_for :quantities, 
                                        reject_if: :all_blank, 
                                        allow_destroy: true

        accepts_nested_attributes_for :ingredients
end

查看成分创建部分：

%strong Ingredients:
  %fieldset#recipe-ingredients
  %br
    = f.fields_for :quantities do |builder|
      = render 'recipe/quantity_fields', f: builder
    .links
      = link_to_add_association 'add ingredient', f, :quantities, 'data-association-insertion-node' => '#recipe-ingredients', 'data-assoication-insertion-moethod' => "append", :wrap_object => Proc.new{|quantity| quantity.ingredient.build ; quantity}
            %br

成分控制器：

class IngredientController < ApplicationController
  before_action :set_ingredient, only: [:show, :edit, :update, :destroy]

  # GET /ingredients
  # GET /ingredients.json
  def index
    @ingredients = Ingredient.all
  end

  # GET /ingredients/1
  # GET /ingredients/1.json
  def show
  end

  # GET /ingredients/new
  def new
    @ingredient = Ingredient.new
  end

  # GET /ingredients/1/edit
  def edit
  end

  def create
    @ingredient = Ingredient.new(ingredient_params)

    respond_to do |format|
      if @ingredient.save
        format.html { redirect_to @ingredient, notice: 'Ingredient was successfully created.' }
        format.json { render :show, status: :created, location: @ingredient }
      else
        format.html { render :new }
        format.json { render json: @ingredient.errors, status: :unprocessable_entity }
      end
    end
  end

  # PATCH/PUT /ingredients/1
  # PATCH/PUT /ingredients/1.json
  def update
    respond_to do |format|
      if @ingredient.update(ingredient_params)
        format.html { redirect_to @ingredient, notice: 'Ingredient was successfully updated.' }
        format.json { render :show, status: :ok, location: @ingredient }
      else
        format.html { render :edit }
        format.json { render json: @ingredient.errors, status: :unprocessable_entity }
      end
    end
  end

  # DELETE /ingredients/1
  # DELETE /ingredients/1.json
  def destroy
    @ingredient.destroy
    respond_to do |format|
      format.html { redirect_to ingredients_url, notice: 'Ingredient was successfully destroyed.' }
      format.json { head :no_content }
    end
  end

  private
    # Use callbacks to share common setup or constraints between actions.
    def set_ingredient
      @ingredient = Ingredient.find(params[:id])
    end

    # Never trust parameters from the scary internet, only allow the white list through.
    def ingredient_params
      params.require(:ingredient).permit(:name)
    end
end

Answer 1

这似乎是一个已知问题，可能是一个错误。检查这个：https://github.com/rails/rails/issues/20676

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