创建表单后无法保存Params值

Question

目前，我可以提交和创建我的表单。但是，问题是，我的表中有一个字段具有nill值，即created_by列。我不知道它的值传递到哪里，因为它不会抛出任何错误。我猜想，我的创建方法无法将current_user.id的值传递到商品组表中的字段created_by中，而且我认为我已经正确地设置了用户和商品组之间的关系。基本上，如果用户创建一个商品组，他的id将保存到表商品组中的created_by列中，如果他更新商品组上的信息，他的id将保存到update_by列中，这样我就可以通过这样的操作将他的名字或电子邮件检索到视图中：

<p>
Created by: <%= @commodity_group.user.name %> 
Updated by: <%= @commodity_group.user.name %>
</p>

更新:我不知道，不知怎么的，current_user.id现在可以保存到列created_by中了。但是，当我调用<%= @commodity_group.user.name %>时，会得到以下错误：

用于nil的未定义方法“`name”：NilClass

以下是所有文件：

user.rb:

class User < ActiveRecord::Base
  extend FriendlyId
  include Filterable

  friendly_id :slug_candidates, use: :history
  has_secure_password
  acts_as_paranoid

  has_many :activities
  has_many :pricing_histories

  has_many :commodity_groups_created, class_name: 'CommodityGroup',
                                      foreign_key: :created_by
  has_many :commodity_groups_updated, class_name: 'CommodityGroup',
                                      foreign_key: :updated_by
end

commodity_group.rb:

class CommodityGroup < ActiveRecord::Base
  extend FriendlyId
  friendly_id :code, use: :history

  belongs_to :created_user,
             class_name: 'User',
             primary_key: :id,
             foreign_key: :created_by
  belongs_to :updated_user,
             class_name: 'User',
             primary_key: :id,
             foreign_key: :updated_by

  validates_presence_of :code
  validates_presence_of :name
  # validates_presence_of :user
end

commodity_groups/_form.html.haml

%div.page-content-wrapper
  %div.page-content
    = render 'header'
    %div.row
      .col-md-12
        .portlet.light.form-fit
          .portlet-title
            - if defined? title
              .caption
                %i.icon-user.font-blue-hoki
                %span.caption-subject.font-blue-hoki.bold.uppercase
                  = title
          .portlet-body.form
            = form_for @commodity_group, html: {class: 'form-horizontal form-bordered form-label-stripped'} do |f|
              .form-body
                .form-group
                  %label.control-label.col-md-3 Code
                  .col-md-9
                    = f.text_field :code, placeholder: 'Code', class: 'form-control'
                .form-group.last
                  %label.control-label.col-md-3 Name
                  .col-md-9
                    = f.text_field :name, placeholder: 'Name', class: 'form-control'
              .form-actions
                .row
                  .col-md-offset-3.col-md-9
                    %button.btn.green{:type => 'submit'}
                      %i.fa.fa-check
                      Submit
                    = link_to "Cancel", locations_path, class: 'btn default'

commodity_groups_controller.rb:

class CommodityGroupsController < ApplicationController
  before_action :set_commodity_group, only: [:show, :edit, :update, :destroy]

  # GET /commodity_groups
  def index
    @commodity_groups = CommodityGroup.all
  end

  # GET /commodity_groups/1
  def show
  end

  # GET /commodity_groups/new
  def new
    @commodity_group = current_user.commodity_groups_created.build
  end

  # GET /commodity_groups/1/edit
  def edit
  end

  # POST /commodity_groups
  def create
    @commodity_group = current_user.commodity_groups_created.create(commodity_group_params)

    if @commodity_group.save!
      redirect_to commodity_groups_path, notice: init_message(:success, t('message.new_success', page_name: t('page_name.commodity_group')))
    else
      redirect_to new_commodity_group_path, notice: init_message(:error, t('message.new_error', page_name: t('page_name.commodity_group')))
    end
  end

  # PATCH/PUT /commodity_groups/1
  def update
    if @commodity_group.update(commodity_group_params)
      @commodity_group.update_columns(created_by: current_user.id)

      redirect_to @commodity_group, notice: 'Commodity group was successfully updated.'
    else
      render :edit
    end
  end

  # DELETE /commodity_groups/1
  def destroy
    @commodity_group.destroy
    redirect_to commodity_groups_url, notice: 'Commodity group was successfully destroyed.'
  end

  private
    # Use callbacks to share common setup or constraints between actions.
    def set_commodity_group
      @commodity_group = CommodityGroup.find(params[:id])
    end

    # Only allow a trusted parameter "white list" through.
    def commodity_group_params
      params.require(:commodity_group).permit(:code, :name, :created_by, :updated_by, :slug)
    end
end

Answer 1

首先，检查用户id是否正确保存了commodity_object。

如果不是，

请上传从表单中发送的表单和参数。

如果是，，

在commodity_group.rb文件中，您用相同的代码给出了两个belongs_to关系，这是错误的，因此它在created_by and updated_by需要什么关系时感到困惑。

按以下方式更改文件，

class CommodityGroup < ActiveRecord::Base
  extend FriendlyId
  friendly_id :code, use: :history

  belongs_to :created_user,
             class_name: 'User',
             primary_key: :id,
             foreign_key: :created_by
  belongs_to :updated_user,
             class_name: 'User',
             primary_key: :id,
             foreign_key: :updated_by

  validates_presence_of :code
  validates_presence_of :name
  # validates_presence_of :user
end

仔细观察两个belongs_to名称。现在可以调用，

<%= @commodity_group.created_user.name %> 
<%= @commodity_group.updated_user.name %> 

created_user和updated_user将根据这些数据进行分析。