多态嵌套形式

Question

我在创建嵌套多态表单时遇到问题。我正在关注这个问题的解决方案：

Rails: has_many through with polymorphic association - will this work?

描述是：一个人可以有很多事件，每个事件可以有一个多态事件记录

以下是相关型号：

class Event < ActiveRecord::Base
  belongs_to :person
  belongs_to :eventable, :polymorphic => true
end

class Meal < ActiveRecord::Base
  has_one :event, :as => eventable
end

class Workout < ActiveRecord::Base
  has_one :event, :as => eventable
end

class Person < ActiveRecord::Base
  has_many :events
  has_many :meals, :through => :events, :source => :eventable,
    :source_type => "Meal"
  has_many :workouts, :through => :events, :source => :eventable,
    :source_type => "Workout"
end

我的控制器如下所示：

def 
  @person = Person.new
  @person.meals.new
  @person.workouts.new
new

我的观点是这样的：

<%=  form_for @person do |person| %>
 <%= person.fields_for :meals, @person.meals.build do |meals| %>
   <%= meals.text_field :food %>
  <% end %>
<% end %>

我目前遇到的错误是：

未知属性：person_id

我认为多态关联阻碍了对象的创建，因为在创建人之前无法创建餐点？我是否正确设置了表格？谢谢！

Answer 1

您需要在events 表中包含person_id 属性（根据belongs_to 关联）

还有一些其他问题你应该解决：

---

控制器

def new
    @person = Person.build
end

def create
    @person = Person.new(person_attributes)
    @person.save
end

private

def person_attributes
    params.require(:person).permit(:your, :attributes, events_attributes: [:eventable_type, :eventable_id, meal_attributes: [:params], workout_attributes: [:params]])
end

---

模型

#app/models/person.rb
Class Person < ActiveRecord::Base
    has_many :events
    has_many :meals, :through => :events, :source => :eventable,
        :source_type => "Meal"
    has_many :workouts, :through => :events, :source => :eventable,
        :source_type => "Workout"

    def self.build
        person = Person.new
        person.events.build.build_meal
        person.events.build.build_workout
    end

end

---

观看次数

#app/views/people/new.html.erb
<%=  form_for @person do |person| %>
 <%= person.fields_for :events do |e| %>
   <%= e.fields_for :meal %>
       <%= e.text_field :food %>
   <% end %>
  <% end %>
<% end %>