Question

创建新记录时出现错误，我遇到了问题：

NoMethodError in CoffeeRoastsController#create
undefined method `name' for #<CoffeeBlend:0x007f95a0d168d8>

我正在尝试创建一个具有has_many coffee_roast的新coffee_blends，这是一个也具有has_many coffee_beans的联接表。我的coffee_roast/_form.html.erb拥有一个精选集合，可以浏览各种coffee_beans

_form

<%= form_with(model: coffee_roast, local: true) do |form| %>
  <% if coffee_roast.errors.any? %>
    <div id="error_explanation">
      <h2><%= pluralize(coffee_roast.errors.count, "error") %> prohibited this coffee_roast from being saved:</h2>

      <ul>
      <% coffee_roast.errors.full_messages.each do |message| %>
        <li><%= message %></li>
      <% end %>
      </ul>
    </div>
  <% end %>

   <div class="col-6">
    <div class="field form-group">
      <%= form.label :roaster, class: 'control-label' %><br />
      <%= form.collection_select(:roaster_id, Roaster.order(:roaster_name), :id, :roaster_name, :prompt => 'Choose Roaster') %>
    </div>

  <div class="field">
    <strong><%= form.label :name %></strong>
    <%= form.text_field :name, id: :coffee_roast_name %>
  </div>

  <div class="field form-group">
    <%= collection_check_boxes :coffee_roast, :coffee_bean_ids, CoffeeBean.all.order(name: :asc), :id, :name do |cb| %>
    <% cb.label(class: "checkbox-inline input_checkbox") {cb.check_box(class: "checkbox") + cb.text } %>
    <% end %>
  </div>

    <div class="field form-group">
      <%= collection_check_boxes :coffee_roast, :flavour_ids, Flavour.all.order(name: :asc), :id, :name do |cb| %>
      <% cb.label(class: "checkbox-inline input_checkbox") {cb.check_box(class: "checkbox") + cb.text } %>
      <% end %>
    </div>

  <div class="form-group">
    <%= form.label :style, "Style", class: 'control-label' %><br />
    <%= form.select :style, [ 'Espresso','Filter' ], :prompt => 'Select One', id: :coffee_style, class: "form-control" %>
  </div>

  <div class="form-group">
    <%= form.label :strength, "Strength", class: 'control-label' %><br />
    <%= form.select :strength, [ 'Light','Medium','Dark' ], :prompt => 'Select One', id: :coffee_strength, class: "form-control" %>
  </div>


  <div class="form-group">
    <%= form.label :image %>
    <%= form.file_field :image, id: :coffee_roast_image %>
  </div>

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

如果不选择任何bean，我就可以创建记录。

由于错误表明name是CoffeeBlend的未定义方法，我怀疑该collection_select中存在潜在的错误，但我无法弄清楚它会是什么。

我能够创建新的coffee_beans，因此可以很好地更新coffee_blend joins表。

模型

class CoffeeBlend < ApplicationRecord
    belongs_to :coffee_bean
    belongs_to :coffee_roast

class CoffeeBean < ApplicationRecord

    has_many :coffee_blends
    has_many :coffee_roasts, through: :coffee_blends
    belongs_to :country

class CoffeeRoast < ApplicationRecord
    belongs_to :roaster
    has_many :coffee_blends
    has_many :coffee_beans, through: :coffee_blends

    has_one_attached :image

控制器

  def create
    @coffee_roast = CoffeeRoast.new(coffee_roast_params)

    respond_to do |format|
      if @coffee_roast.save
        format.html { redirect_to @coffee_roast, notice: 'Coffee roast was successfully created.' }
        format.json { render :show, status: :created, location: @coffee_roast }
      else
        format.html { render :new }
        format.json { render json: @coffee_roast.errors, status: :unprocessable_entity }
      end
    end
  end

控制台

Started POST "/coffee_roasts" for 127.0.0.1 at 2019-01-04 08:17:05 +0000
Processing by CoffeeRoastsController#create as HTML
  Parameters: {"utf8"=>"✓", "authenticity_token"=>"+MbuyujdR1gSTRaylqeUjto4ZqhgnNnGfnPRiNEevdu2wePduXtEugbtmNpx6HGrtivFWZC92KGwTGJSy9+A2A==", "coffee_roast"=>{"roaster_id"=>"6", "name"=>"Revelation", "coffee_bean_ids"=>["", "4", "5"], "flavour_ids"=>["", "3", "2"], "style"=>"Espresso", "strength"=>"Dark"}, "commit"=>"Create Coffee roast"}
  CoffeeBean Load (44.8ms)  SELECT "coffee_beans".* FROM "coffee_beans" WHERE "coffee_beans"."id" IN ($1, $2)  [["id", 4], ["id", 5]]
  Flavour Load (0.9ms)  SELECT "flavours".* FROM "flavours" WHERE "flavours"."id" IN ($1, $2)  [["id", 3], ["id", 2]]
   (1.0ms)  BEGIN
  CoffeeRoast Exists (43.7ms)  SELECT  1 AS one FROM "coffee_roasts" WHERE "coffee_roasts"."id" IS NOT NULL AND "coffee_roasts"."slug" = $1 LIMIT $2  [["slug", "revelation"], ["LIMIT", 1]]
  Roaster Load (0.8ms)  SELECT  "roasters".* FROM "roasters" WHERE "roasters"."roaster_id" = $1 LIMIT $2  [["roaster_id", 6], ["LIMIT", 1]]
   (0.6ms)  ROLLBACK
Completed 500 Internal Server Error in 280ms (ActiveRecord: 116.2ms)



NoMethodError (undefined method `name' for #<CoffeeBlend:0x007f95a3ad10e8>):

Answer 1

感谢@vasilisa，她发现我试图在slug联接表中创建一个coffee_blend，其中没有名为:name的字段

无法在Rails 5.2中创建记录

1 个答案: