无法保存数据活动管理员 slef 关联 Rails 5.2答案

【问题标题】：unable to save data active admin slef association rails 5.2无法保存数据活动管理员 slef 关联 Rails 5.2
【发布时间】：2020-03-10 18:00:20
【问题描述】：

数据库结构

id | name | category_id(parent_id) |

当我尝试使用活动管理员保存数据时，它会显示以下错误消息，请在下面找到详细信息以及模型。

processing by Admin::CategoriesController#create as HTML
  Parameters: {"utf8"=>"✓", "authenticity_token"=>"Wj+Au5xC6mfESE/OXhLNM8a33Sy9Arr0pXvDnpAZdJxo/wfOLXhklVnkUbfdvEaUN0deAh78jqUqDIyCLCjwKQ==", "category"=>{"name"=>"tech", "category_id"=>"2"}, "commit"=>"Create Category"}
  User Load (1.0ms)  SELECT  "users".* FROM "users" WHERE "users"."id" = $1 ORDER BY "users"."id" ASC LIMIT $2  [["id", 1], ["LIMIT", 1]]
  ↳ /home/adi/.rvm/gems/ruby-2.5.7/gems/activerecord-5.2.4.1/lib/active_record/log_subscriber.rb:98
   (0.4ms)  BEGIN
  ↳ /home/adi/.rvm/gems/ruby-2.5.7/gems/activerecord-5.2.4.1/lib/active_record/log_subscriber.rb:98
   (0.4ms)  ROLLBACK
  ↳ /home/adi/.rvm/gems/ruby-2.5.7/gems/activerecord-5.2.4.1/lib/active_record/log_subscriber.rb:98
  Rendering /home/adi/.rvm/gems/ruby-2.5.7/gems/activeadmin-1.4.3/app/views/active_admin/resource/new.html.arb
  Category Load (0.8ms)  SELECT "categories".* FROM "categories"
  ↳ app/admin/categories.rb:16
  Rendered /home/adi/.rvm/gems/ruby-2.5.7/gems/activeadmin-1.4.3/app/views/active_admin/resource/new.html.arb (640.2ms)
Completed 200 OK in 746ms (Views: 644.9ms | ActiveRecord: 15.8ms)


Started POST "/admin/categories" for 127.0.0.1 at 2020-03-10 23:14:52 +0530
Processing by Admin::CategoriesController#create as HTML
  Parameters: {"utf8"=>"✓", "authenticity_token"=>"WNo/hAr1v+g75CQeyTPTFH2J8u9OuOhPM4bLPPFGKnRqGrjxu88xGqZIOmdKnVizjHlxwe1G3B688YQgTXeuwQ==", "category"=>{"name"=>"tech", "category_id"=>"2"}, "commit"=>"Create Category"}
  User Load (0.8ms)  SELECT  "users".* FROM "users" WHERE "users"."id" = $1 ORDER BY "users"."id" ASC LIMIT $2  [["id", 1], ["LIMIT", 1]]
  ↳ /home/adi/.rvm/gems/ruby-2.5.7/gems/activerecord-5.2.4.1/lib/active_record/log_subscriber.rb:98
   (0.3ms)  BEGIN
  ↳ /home/adi/.rvm/gems/ruby-2.5.7/gems/activerecord-5.2.4.1/lib/active_record/log_subscriber.rb:98
   (0.3ms)  ROLLBACK
  ↳ /home/adi/.rvm/gems/ruby-2.5.7/gems/activerecord-5.2.4.1/lib/active_record/log_subscriber.rb:98
  Rendering /home/adi/.rvm/gems/ruby-2.5.7/gems/activeadmin-1.4.3/app/views/active_admin/resource/new.html.arb
  Category Load (0.7ms)  SELECT "categories".* FROM "categories"
  ↳ app/admin/categories.rb:16
  Rendered /home/adi/.rvm/gems/ruby-2.5.7/gems/activeadmin-1.4.3/app/views/active_admin/resource/new.html.arb (147.3ms)
Completed 200 OK in 179ms (Views: 152.4ms | ActiveRecord: 2.6ms)

型号：-

class Category < ApplicationRecord
    has_many :blogs
    belongs_to :category, :class_name => 'Category'
    has_many :category, :class_name => 'Category', :foreign_key => 'category_id'
    # belongs_to :Category, :class_name => 'Category'
    scope :category_name, -> (id) { find(id).name }
end

活跃的管理员

ActiveAdmin.register Category do
    permit_params :name, :category_id

    index do
      selectable_column
      id_column
      column :name
      column :category_id
      actions
    end


    form do |f|
      f.inputs do
        f.input :name
        f.input :category_id, :label => 'Category',:as => :select, :class => 'form-control',:collection => Category.all.map{|category| ["#{category.name}", category.id]}
      end
      f.actions
    end

end

我也希望它是这样选择的，如果我有 2 个 id 为 1 和 2 的父类别音乐和视频，以及 2 个类别 id 为 1 的子摇滚和无声音乐，那么如果我选择父类别音乐，则子类别下拉列表会自动包含摇滚和无声音乐值。

【问题讨论】：

我没有看到错误信息？拥有同名（类别）的belong_to 和has_many 是自找麻烦。如果这是您的意图，请使用 Google 'activerecord tree'。
ROLLBACK 消息不允许存储数据
ROLLBACK 没有多大帮助。尝试将此添加到您的类别类：after_validation { Rails.logger.debug errors.inspect unless errors.empty? }

标签： ruby ruby-on-rails-5 activeadmin self-reference

【解决方案1】：

可能发生了一些验证错误。如果您像下面这样定义关联，您将拥有一个更好的系统 -

  belongs_to :parent_category, foreign_key: 'category_id', class_name: 'Category', optional: true
  has_many :sub_categories, class_name: 'Category', foreign_key: 'category_id',
           dependent: :destroy

然后通常您可以轻松访问 sub_categories 和 parent_category。希望 active_admin 错误会消失。如果 active_admin 中还有任何错误，请发表评论。

【讨论】：