Question

我有一个非常基本的问题，但似乎无法让它正常工作。

这是设置 -

class Recipe < ActiveRecord::Base
 has_many :recipeIngredients
 has_many :ingredients :through => :recipeIngredients
end

class Ingredient < ActiveRecord::Base
 has_many :recipeIngredients
 has_many :recipes :through => :recipeIngredients
end

class RecipeIngredients < ActiveRecord::Base
 belongs_to :recipe
 belongs_to :ingredients
end

每种成分都有ID和名称，Recipe有ID和标题，RecipeIngredients有recipe_id，ingredient_id，金额

当我尝试使用

进行渲染时

@recipe = Recipe.find(params[:id])
render :json => @recipe, :include => :ingredients

我得到了我的成分，但无法从RecipeIngredients访问金额或名称。 - 这输出

{
    "list_items": {
        "id": 1,
        "title": "Foo",
        "description": null,
        "ingredients": [
            {
                "id": 1
            },
            {
                "id": 2
            },
            {
                "id": 3
            },
            {
                "id": 4
            }
        ]
    }
}

如何在成分和配方成分之间建立关系，以便在调用时：我会得到类似的东西 -

{
 "id":1,
 "name":"foo",
 "amount":"2 oz"
}

谢谢！

Answer 1

根据Rails，你没有定义多对多。正确的解决方案是（文件名应该如上所述）：

应用/模型/ recipe.rb

class Recipe < ActiveRecord::Base has_many :recipe_ingredients has_many :ingredients, :through => :recipe_ingredients end

应用/模型/ ingredient.rb

class Ingredient < ActiveRecord::Base has_many :recipe_ingredients has_many :recipes, :through => :recipe_ingredients end

应用/模型/ recipe_igredient.rb

class RecipeIngredient < ActiveRecord::Base belongs_to :recipe belongs_to :ingredient end

同时验证，您的连接表定义如下：

<强>分贝/ 12345_create_recipe_ingredints.rb

class CreateRecipeIngredients < ActiveRecord::Migration def change create_table :recipe_ingredients, id: false do |t| t.references :recipe t.references :ingredient end add_index :recipe_ingredients, :recipe_id add_index :recipe_ingredients, :ingredient_id end end

执行此操作后，在控制台中进行测试：

recipe = Recipe.first # should contain data igredient = Ingredient.first # should contain data recipe.ingredients << ingredient recipe.inspect

如果一切正常并且 recipe.inspect 包含成分，则json应该是正确的

Rails has_many belongs_to关系

1 个答案: