嵌套属性无法保存在数据库中?不显示值-Ruby on Rails [英] Nested attributes not saving in database? Does not display values - Ruby on Rails

问题描述

我有一个嵌套的属性，可以显示值，但是为什么没有将其保存到数据库中?

I have a nested attribute and I can display values, but it is not saving into database why?

我有一个模型review，我想嵌套属性comments

I have a model review and I want to nest attribute comments

查看迁移文件

class CreateReviews < ActiveRecord::Migration
  def change
    create_table :reviews do |t|
      t.belongs_to :reviewable, polymorphic: true
      t.timestamps
    end
    add_index :reviews, [:reviewable_id, :reviewable_type]

  end
end

评论模型

class Review < ActiveRecord::Base
  attr_accessible :rating, :user_id, :comments_attributes, :service
  has_many :comments, as: :commentable
  belongs_to :user
  belongs_to :reviewable, polymorphic: true

  accepts_nested_attributes_for :comments

end

评论迁移文件

class CreateComments < ActiveRecord::Migration
  def change
    create_table :comments do |t|
      t.text :content
      t.belongs_to :commentable, polymorphic: true
      t.integer :user_id
      t.timestamps
    end
    add_index :comments, [:commentable_id, :commentable_type]
  end
end

评论模型

class Comment < ActiveRecord::Base
  attr_accessible :content, :user_id
  belongs_to :commentable, polymorphic: true
  belongs_to :user
  belongs_to :review
end

这是表格

<%= form_for [@reviewable, @review], :html => {:multipart => true} do |f| %>

  <%= f.fields_for :comments, @review.comments.build do |field| %>
    <%= field.label "Comment" %></div>
    <%= field.text_field :content %>
  <% end %>

  <%= f.submit %>
<% end %>

它显示字段，但是保存时为什么不保存呢?

It displays the fields, but how come when I save, it doesn't save?

我试图这样显示:

<%= @review.comments %>

这是我的评论控制者

  def new
    @review = @reviewable.reviews.new
    @review.comments.build
  end

感谢您的帮助！

查看控制器:创建方法

  def create
    @review = @reviewable.reviews.new(params[:review])
    @review.user = current_user
    if @review.save
      redirect_to @reviewable, notice: "review created."
    else
      render :new
    end
  end

推荐答案

您的控制器和视图中似乎存在一些混乱的逻辑

There seems to be some muddled logic in your controller and views

  def new
    @review = @reviewable.reviews.new
    @review.comments.build
  end

在这里您正在呼叫@reviewable.reviews.new，但是@reviewable尚不存在.一种更常见的调用方式是Review.new

Here you are calling @reviewable.reviews.new, but @reviewable doesn't yet exist. A more usual way of calling this would be Review.new

接下来，您要执行此操作

Next in your view you do this

<%= form_for [@reviewable, @review], :html => {:multipart => true} do |f| %>

  <%= f.fields_for :comments, @review.comments.build do |field| %>

这会将@reviewable和@review传递给form_for.这似乎很奇怪.使用嵌套，您通常只需要传递顶级实例变量，即@review.

This is passing @reviewable and @review to the form_for. This seems odd. With nesting you would normally only need to pass the top level instance variable i.e. @review.

接下来，当您进入fields_for时，您将传递:comments和@review.comments.build.一般来说，这只需要:comment，因为您已经在控制器中建立了注释.

Next, when you get to fields_for you are passing :comments and @review.comments.build. Generally speaking this should only require :comment, because you've already built the comment in the controller.

我建议您查看这两个截屏视频

I would recommend that you review these two screencasts

http://railscasts.com/episodes/196-nested- model-form-part-1 http://railscasts.com/episodes/197-nested-model-form -part-2

还有许多宝石可以处理使事物变得雄辩可言的整个过程，可以在这里找到

There are also a number of Gems that handle the whole process of making things commentable very eloquently, they can be found here

https://www.ruby-toolbox.com/categories/rails_comments

我认为值得评论的宝石之路更好，因为它们正在由更大的社区进行研究，从长远来看，我认为最终要比个人创造更好.

I think the commentable Gems path is better because they are being worked on by a larger community and I think end up being better than personal creations in the long term.

希望这对您有帮助...

Hope this helps...

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