Ruby on rails 嵌套资源不会创建数据，在事务开始后立即回滚事务

我的问题是不会创建嵌套在帖子中的标签

我有一个贴子，里面嵌套了标签。像这样

resources :posts do
  resources :tags, :only => [:new, :create, :destroy]
end

在我的标签控制器里我有这个

class TagsController < ApplicationController
  before_filter :authenticate_user!

  def new
    @post = Post.find(params[:post_id])
    @tag = Tag.new
  end

  def create
    @post = Post.find(params[:post_id])
    @tag = @post.tags.build(params[:tags])

    if @tag.save 
      flash[:notice] = "Tag created"
      redirect_to @tag.post
    else
      flash[:error] = "Could not add tag at this time"
      redirect_to @tag.post
    end
  end
end

---

您的

TagsController的
create（）
操作中有输入错误：

@tag=@post.tags.build（params[：tags]）

用于创建标记的哈希应该是
params[：tag]
，而不是
params[：tags]
标记控制器的
create（）
操作中存在键入错误：

@tag=@post.tags.build（params[：tags]）

用于创建标记的散列应该是
params[：tag]
，而不是
params[：tags]
您可以通过在服务器控制台中使用
p@tag.errors
或
p@tag.errors.full\u消息来调试错误。现在我可以创建一个标记，但是tagable_type和tagable_id的字段没有被创建，即使我在表单字段中键入了两个值。请在那里提供模型，感谢我的创建操作中我有@tag=@post.tags.build（params[：tags]），应该在params中标记，而不是标记。您可以通过在服务器控制台中使用
p@tag.errors
或
p@tag.errors.full_消息打印来调试错误。现在我可以创建一个标记，但是tagable_type和tagable_id的字段没有被创建，即使我在表单字段中键入了两个值。请在那里提供模型，感谢我的创建操作中我有@tag=@post.tags.build（params[：tags]），应该在params中标记，而不是标记。叹息
<%= form_for [@post, @tag] do |f| %>
  <% if @tag.errors.any? %>
    <div id="error_explanation">
      <h2><%= pluralize(@tag.errors.count, "error") %> prohibited this tag from being saved:</h2>

      <ul>
      <% @tag.errors.full_messages.each do |msg| %>
        <li><%= msg %></li>
      <% end %>
      </ul>
    </div>
  <% end %>

  <div class="field">
    <%= f.text_field :tagable_type, :placeholder => "Type" %>
  </div>

  <div class="field">
    <%= f.text_field :tagable_id, :placeholder => "Id" %>
  </div>

  <div class="actions">
    <%= f.submit %>
  </div>
<% end %>

class Tag < ActiveRecord::Base
  attr_accessible :post_id, :user_id, :tagable_type, :tagable_id

  validates :post_id, presence: true

  belongs_to :tagable, :polymorphic => true
  belongs_to :post
  belongs_to :user
end

class Post < ActiveRecord::Base
  attr_accessible :body, :link, :thumbnail, :title, :user_id, :youtube, :youtube_id, :website_name, :image_field

  default_scope order: 'posts.active DESC'

  has_many :tags, :dependent => :destroy
  has_many :comments, :as => :commentable, :dependent => :destroy

  belongs_to :user
end

Started POST "/posts/18/tags" for 127.0.0.1 at 2013-06-26 15:54:14 +0200
Processing by TagsController#create as HTML
  Parameters: {"utf8"=>"✓", "authenticity_token"=>"gwpTs0Qqcrre4tH974RrfpaENGZKtSbkJx2U0H67AcM=", "tag"=>{"tagable_type"=>"Player", "tagable_id"=>"2"}, "commit"=>"Create Tag", "post_id"=>"18"}
  User Load (0.3ms)  SELECT "users".* FROM "users" WHERE "users"."id" = 1 LIMIT 1
  Post Load (0.1ms)  SELECT "posts".* FROM "posts" WHERE "posts"."id" = ? ORDER BY posts.active DESC LIMIT 1  [["id", "18"]]
   (0.1ms)  begin transaction
  SQL (0.4ms)  INSERT INTO "tags" ("created_at", "post_id", "tagable_id", "tagable_type", "updated_at", "user_id") VALUES (?, ?, ?, ?, ?, ?)  [["created_at", Wed, 26 Jun 2013 13:54:14 UTC +00:00], ["post_id", 18], ["tagable_id", nil], ["tagable_type", nil], ["updated_at", Wed, 26 Jun 2013 13:54:14 UTC +00:00], ["user_id", 1]]
   (6.9ms)  commit transaction
  Post Load (0.2ms)  SELECT "posts".* FROM "posts" WHERE "posts"."id" = 18 ORDER BY posts.active DESC LIMIT 1
Redirected to http://localhost:3000/posts/18
Completed 302 Found in 15ms (ActiveRecord: 7.9ms)