Ruby on rails Rails集合\u选择多对多不在联接表中创建条目

我正在开发一个类似于图书馆预订的应用程序。我一直在为添加新书而构建嵌套表单。我得到了一对多关系（一本书的图像等）的表单，但我还想选择一个现有作者，并将其与该书（一本书有许多作者，一个作者通过贡献表有许多书）绑定在一起

提交表单时，它不会在联接表中使用book_id和author_id创建条目。（在创建新作者时，我设法让它使用简单的文本输入字段，但集合\u select不起作用。在将reject\u if添加到accepts\u嵌套的\u属性之前，它一直使用空的first\u name和last\u name创建一个新作者，并使用此空的新作者在联接表中创建一个条目）

这是我的表格，只剩下重要的部分

    <%= form_for @book do |f| %>

    <div class="panel panel-default">
        <div class="panel-body">
            <%= f.label :name, "Book title" %>
            <%= f.text_field :name %>
            <%= f.label :description %>
            <%= f.text_area :description, rows: 5 %>
            <%= f.label :year_of_publication %>
            <%= f.text_field :year_of_publication %>
        </div>
    </div>

    <div class="panel panel-default">
        <div class="panel-body">
            <h3>Add authors</h3>
            <h4>Choose from existing authors</h4>
            <%= f.fields_for :authors do |builder| %>
                <%= builder.collection_select( :id, Author.all, :id, :full_name, prompt: "Select from existing authors") %>
            <% end %>
        </div>
    </div>

    <%= f.submit "Submit", class: "btn btn-info" %>
<% end %>

BooksController中的“新建”和“创建”操作

def new
@book = Book.new

# Displays empty fields in the new book action view (n.times)
1.times { @book.authors.build }
1.times { @book.book_images.build }
@book.stock_items.build
end

def create

@book = Book.new(book_params)

if @book.save
  redirect_to @book
  flash[:success] = "Book added"
else
  render 'new'
  flash.now[:danger] = "Book NOT added"
end
end

我的书

私人的

def book_params
  # Include the nested parameters in the strong parameters as model_name_attributes !!!!!!!!!!
  params.require(:book).permit( :name, 
                                :description, 
                                :year_of_publication, 
                                authors_attributes: [ :first_name, :last_name ], 
                                book_images_attributes: [ :image_url, :book_id ], 
                                libraries_attributes: [ :name ], 
                                stock_item_attributes: [ :book_id, :library_id ], 
                                contribution_attributes: [ :book_id, :author_id ])
end

---

你能展示你在多对多关系中使用的所有三个模型吗

class Physician < ActiveRecord::Base
attr_accessible :name, :title
  has_many :appointments
  has_many :patients, through: :appointments
end

class Appointment < ActiveRecord::Base
 attr_accessible :details, :patient_id, :physician_id
  belongs_to :physician
  belongs_to :patient
end

class Patient < ActiveRecord::Base
  attr_accessible :name , :details
  has_many :appointments
  has_many :physicians, through: :appointments
end

class医生

---

关系定义本身应该有一些问题，这通常是直接起作用的

如果我理解正确，您应该利用您的

加入表贡献

。将

部分的
字段更改为这将使其起作用

<div class="panel panel-default">
        <div class="panel-body">
            <h3>Add authors</h3>
            <h4>Choose from existing authors</h4>
            <%= f.fields_for :contributions do |builder| %>
            <%= builder.collection_select(:author_id, Author.all, :id, :full_name, prompt: "Select from existing authors") %>
            <% end %>
        </div>
    </div>


添加作者
从现有作者中选择
这行
应该是
吗？谢谢你的评论！如果我尝试这一点，我会在书中看到一个命名错误#new。未定义的方法“merge”表示：full\u name:Symbol我不太确定这是什么意思（我在上面的作者模型中定义了full\u name）。再次感谢！您可以在提交
表单后发布
日志信息吗？
？抱歉，我忘了删除您建议行中的：id。我尝试了您所说的内容，现在我为#获得了一个未定义的方法“author_id”。可能您应该将这行
更改为
，然后尝试我的第一个建议。谢谢，我已经添加了代码的贡献模型，请看一看。确切地说，我以前尝试过这一点，但没有成功，因为这一行已经存在，花了我整整两天的时间：
验证：book_id，presence:true
按照Pavan在回答中的建议执行，并删除我的书模型中的行使其成功。谢谢！
  create_table "authors", force: true do |t|
    t.string   "last_name"
    t.string   "first_name"
    t.datetime "created_at"
    t.datetime "updated_at"
  end

  create_table "contributions", force: true do |t|
    t.integer  "book_id"
    t.integer  "author_id"
    t.datetime "created_at"
    t.datetime "updated_at"
  end

  create_table "books", force: true do |t|
    t.string   "name"
    t.datetime "created_at"
    t.datetime "updated_at"
    t.string   "year_of_publication"
    t.string   "description"
  end

def new
@book = Book.new

# Displays empty fields in the new book action view (n.times)
1.times { @book.authors.build }
1.times { @book.book_images.build }
@book.stock_items.build
end

def create

@book = Book.new(book_params)

if @book.save
  redirect_to @book
  flash[:success] = "Book added"
else
  render 'new'
  flash.now[:danger] = "Book NOT added"
end
end

def book_params
  # Include the nested parameters in the strong parameters as model_name_attributes !!!!!!!!!!
  params.require(:book).permit( :name, 
                                :description, 
                                :year_of_publication, 
                                authors_attributes: [ :first_name, :last_name ], 
                                book_images_attributes: [ :image_url, :book_id ], 
                                libraries_attributes: [ :name ], 
                                stock_item_attributes: [ :book_id, :library_id ], 
                                contribution_attributes: [ :book_id, :author_id ])
end

class Physician < ActiveRecord::Base
attr_accessible :name, :title
  has_many :appointments
  has_many :patients, through: :appointments
end

class Appointment < ActiveRecord::Base
 attr_accessible :details, :patient_id, :physician_id
  belongs_to :physician
  belongs_to :patient
end

class Patient < ActiveRecord::Base
  attr_accessible :name , :details
  has_many :appointments
  has_many :physicians, through: :appointments
end

<div class="panel panel-default">
        <div class="panel-body">
            <h3>Add authors</h3>
            <h4>Choose from existing authors</h4>
            <%= f.fields_for :contributions do |builder| %>
            <%= builder.collection_select(:author_id, Author.all, :id, :full_name, prompt: "Select from existing authors") %>
            <% end %>
        </div>
    </div>