Question

我收到以下错误... ActiveRecord :: AssociationTypeMismatch设备（#xxxx）预期，得到字符串（#xxxx）

我无法确定这个错误的来源或解决方法。任何人都可以解释我的代码出错的地方吗？

Models =

class Device < ActiveRecord::Base

  has_many :from_links, class_name: "Link", foreign_key: "from_device"
  has_many :to_links, class_name: "Link", foreign_key: "to_device"

  def connected_devices
    from_links.map(&:to_device) + to_links.map(&:from_device)
  end
end

class Link < ActiveRecord::Base

  belongs_to :from_device, class_name: "Device"
  belongs_to :to_device, class_name: "Device"
end

LinksController =

class LinksController < ApplicationController
  def create
    @link = Link.new(link_params)
    @device = Device.find_by(en: params[:link][:from_device])
    if @link.save
      flash[:success] = "Link created."
      redirect_to device_path(@device)
    else
      render 'new'
    end
  end

 private

   def link_params
     params.require(:link).permit(:from_device, :to_device, device_attributes: [:en])
   end
end

DevicesController =

class DevicesController < ApplicationController

  def show
    @device = Device.find(params[:id])
    @linked_devices = @device.connected_devices
  end

private

  def device_params
    params.require(:device).permit(:name, :en, :system_ip, :router_ip, :pop, :chassis_mode, :code_version)
  end

CreateLinks Database =

class CreateLinks < ActiveRecord::Migration[5.0]
  def change
    create_table :links do |t|
      t.references :from_device
      t.references :to_device
    end
  end

创建新的链接表单=

<% provide(:title, 'New Link') %>
<h1> Create New Link </h1>

<div class="row">
<div class="col-md-6 col-md-offset-3">
  <%= form_for(@link, url: links_path(params[:id])) do |f| %>
    <%= render 'shared/error_messages', object: @link %>

    <%= f.label :from %>
    <%= f.select :from_device, options_for_select(@devices), :include_blank => true, class: 'form-control' %>

    <%= f.label :to %>
    <%= f.select :to_device, options_for_select(@devices), :include_blank => true, class: 'form-control' %>

    <%= f.submit "Submit", class: "btn btn-primary" %>
  <% end %>
</div>

Answer 1

在链接模型中，您与列from_device和to_device建立了关联。您希望通过任何外键关联Links表。如下所示：

has_many :links, foreign_key: "from_device"
has_many :links, foreign_key: "to_device"

看看是否有帮助。您的设备型号也是如此。

ActiveRecord :: AssociationTypeMismatch设备（#xxxx）预期，得到字符串（#xxxx）

1 个答案: