Railsの4コンソール：名エラー：未定義のローカル変数やメソッド＆初期化されていない一定の

Question

Update: It's weird, but right now if I try to migrate something like this:

class RemoveStuffFromTools < ActiveRecord::Migration 
    def change 
    remove_column :tools, :featured, :boolean 
    remove_column :tools, :shares, :integer 
    remove_column :tools, :views, :integer 
    remove_column :tools, :likes, :integer 
    remove_column :tools, :favorites, :integer 
    end 
end 

I get this error:

$ rails g migration remove_stuff_from_tools 
     invoke active_record 
     create db/migrate/20160904090608_remove_stuff_from_tools.rb 

Jonas@JONAS_PC ~/gitapps/ocubit (master) 
$ rake db:migrate 
== 20160904090608 RemoveStuffFromTools: migrating ============================= 
-- remove_column(:tools, :featured, :boolean) 
rake aborted! 
StandardError: An error has occurred, this and all later migrations canceled: 

undefined method `to_sym' for nil:NilClass 
c:/Users/Jonas/gitapps/ocubit/db/migrate/20160904090608_remove_stuff_from_tools.rb:3:in 

change' c:in migrate' NoMethodError: undefined method to_sym' for nil:NilClass c:/Users/Jonas/gitapps/ocubit/db/migrate/20160904090608_remove_stuff_from_tools.rb:3:in change' c:in `migrate' Tasks: TOP => db:migrate (See full trace by running task with --trace)

Is this somehow related?

私はレールやアプリケーションをコーディングする過程でするのは比較的新しいです。これまでのところ、アプリ自体は素晴らしい作品です。最近、私はRailsのコンソールで自分のデータベースを見てみたかったが、私はこれらのエラーを受け取った：

$ rails c 
Loading development environment (Rails 4.2.5.1) 
irb(main):001:0> Tool.last 
NameError: undefined local variable or method `l' for main:Object 
    from (irb):3 
    from c:/RailsInstaller/Ruby2.2.0/lib/ruby/gems/2.2.0/gems/railties-4.2.5.1/lib/rails/commands/console.rb:110:in `start' 
    from c:/RailsInstaller/Ruby2.2.0/lib/ruby/gems/2.2.0/gems/railties-4.2.5.1/lib/rails/commands/console.rb:9:in `start' 
    from c:/RailsInstaller/Ruby2.2.0/lib/ruby/gems/2.2.0/gems/railties-4.2.5.1/lib/rails/commands/commands_tasks.rb:68:in `console' 
    from c:/RailsInstaller/Ruby2.2.0/lib/ruby/gems/2.2.0/gems/railties-4.2.5.1/lib/rails/commands/commands_tasks.rb:39:in `run_command!' 
    from c:/RailsInstaller/Ruby2.2.0/lib/ruby/gems/2.2.0/gems/railties-4.2.5.1/lib/rails/commands.rb:17:in `<top (required)>' 
    from bin/rails:4:in `require' 
    from bin/rails:4:in `<main>' 
irb(main):004:0> Tool.first 
NameError: uninitialized constant T 
    from (irb):5 
    from c:/RailsInstaller/Ruby2.2.0/lib/ruby/gems/2.2.0/gems/railties-4.2.5.1/lib/rails/commands/console.rb:110:in `start' 
    from c:/RailsInstaller/Ruby2.2.0/lib/ruby/gems/2.2.0/gems/railties-4.2.5.1/lib/rails/commands/console.rb:9:in `start' 
    from c:/RailsInstaller/Ruby2.2.0/lib/ruby/gems/2.2.0/gems/railties-4.2.5.1/lib/rails/commands/commands_tasks.rb:68:in `console' 
    from c:/RailsInstaller/Ruby2.2.0/lib/ruby/gems/2.2.0/gems/railties-4.2.5.1/lib/rails/commands/commands_tasks.rb:39:in `run_command!' 
    from c:/RailsInstaller/Ruby2.2.0/lib/ruby/gems/2.2.0/gems/railties-4.2.5.1/lib/rails/commands.rb:17:in `<top (required)>' 
    from bin/rails:4:in `require' 
    from bin/rails:4:in `<main>' 
irb(main):006:0> 

それは私は、この特定のアプリケーションでのRailsコンソールを使用して、それがこれまで働いていた最初の時間ではありません。

私は心配する必要がありますか、またはアプリケーション自体がうまく動作する原因を開発し続ける必要がありますか？ここで

は私のコードです：
私はユーザー

/app/controllers/application_controller.rb

class ApplicationController < ActionController::Base 
    # Prevent CSRF attacks by raising an exception. 
    # For APIs, you may want to use :null_session instead. 
    protect_from_forgery with: :exception 

    before_action :configure_permitted_parameters, if: :devise_controller? 

    protected 

    def configure_permitted_parameters 
     devise_parameter_sanitizer.permit(:sign_up, keys: [:username]) 
     devise_parameter_sanitizer.permit(:account_update, keys: [:username, :phonenumber, :workplace, :website, :twitter, :linkedin, :public_email, :public_phonenumber, :description, :title, :githuburl]) 
    end 
end 

/アプリ/コントローラ/ tools_controllerのための工夫を使用しています.rb

class ToolsController < ApplicationController 
    before_action :find_tool, only: [:show, :edit, :update, :destroy] 
    before_action :authenticate_user! 

    def index 
     @tools = Tool.where(user_id: current_user).order("created_at DESC") 
    end 

    def show 
    end 

    def new 
     @tool = current_user.tools.build 
    end 

    def create 
     @tool = current_user.tools.build(tool_params) 

     if @tool.save 
      redirect_to tools_path 
     else 
      render 'new' 
     end 
    end 

    def edit 
    end 

    def update 
     if @tool.update(tool_params) 
      redirect_to tools_path 
     else 
      render 'edit' 
     end 
    end 

    def destroy 
     @tool.destroy 
     redirect_to tools_path 
    end 

    private 

    def find_tool 
     @tool = Tool.find(params[:id]) 
    end 

    def tool_params 
     params.require(:tool).permit(:title, :subtitle, :url) 
    end 
end 

/app/models/tool.rb

class Tool < ActiveRecord::Base 
    belongs_to :user 
end 

/app/models/user.rb

class User < ActiveRecord::Base 

    # Include default devise modules. Others available are: 

    # :confirmable, :lockable, :timeoutable and :omniauthable 

    devise :database_authenticatable, :registerable, 

     :recoverable, :rememberable, :trackable, :validatable 

    has_many :tools 

end 

/db/schema.rb

# encoding: UTF-8 
# This file is auto-generated from the current state of the database. Instead 
# of editing this file, please use the migrations feature of Active Record to 
# incrementally modify your database, and then regenerate this schema definition. 
# 
# Note that this schema.rb definition is the authoritative source for your 
# database schema. If you need to create the application database on another 
# system, you should be using db:schema:load, not running all the migrations 
# from scratch. The latter is a flawed and unsustainable approach (the more migrations 
# you'll amass, the slower it'll run and the greater likelihood for issues). 
# 
# It's strongly recommended that you check this file into your version control system. 

ActiveRecord::Schema.define(version: 20160902194748) do 

    create_table "tools", force: :cascade do |t| 
    t.string "title" 
    t.string "subtitle" 
    t.string "url" 
    t.boolean "featured" 
    t.integer "shares" 
    t.integer "views" 
    t.integer "likes" 
    t.integer "favorites" 
    t.datetime "created_at", null: false 
    t.datetime "updated_at", null: false 
    t.integer "user_id" 
    end 

    create_table "users", force: :cascade do |t| 
    t.string "email",     default: "", null: false 
    t.string "encrypted_password",  default: "", null: false 
    t.string "reset_password_token" 
    t.datetime "reset_password_sent_at" 
    t.datetime "remember_created_at" 
    t.integer "sign_in_count",   default: 0, null: false 
    t.datetime "current_sign_in_at" 
    t.datetime "last_sign_in_at" 
    t.string "current_sign_in_ip" 
    t.string "last_sign_in_ip" 
    t.datetime "created_at",       null: false 
    t.datetime "updated_at",       null: false 
    t.string "username" 
    end 

    add_index "users", ["email"], name: "index_users_on_email", unique: true 
    add_index "users", ["reset_password_token"], name: "index_users_on_reset_password_token", unique: true 

end 

提供されたd ataは十分ではない場合は教えてください。 あなたのすべての返信に感謝します。

Answer 1

私はそれを理解しました。

db:drop,db:createおよびdb:migrateとした。

すべて正常に機能します。

ご協力いただきありがとうございます。