RoR：テーブルが存在しないエラー

Question

私はこことRoRで新しいです。私は5時間座って、私のプログラムに何が間違っているのか分からない。私は厳格なチュートリアルを続き、これが起こった：

ルビーバージョン：2.2.4 Railsのバージョン：5.0.0.1 工夫バージョン：4.2.0

C:\RailsInstaller\Ruby2.2.0\bin\ruby.exe -e $stdout.sync=true;$stderr.sync=true;load($0=ARGV.shift) C:/Benutzer/Clemens/RubymineProjects/RubyAndroid/bin/rails db:migrate 
rails aborted! 
StandardError: An error has occurred, all later migrations canceled: 

Mysql2::Error: Table 'rubyandroid_development.users' doesn't exist: CREATE UNIQUE INDEX `index_users_on_authentication_token` ON `users` (`authentication_token`) 
C:/Benutzer/Clemens/RubymineProjects/RubyAndroid/db/migrate/20160826225028_devise_create_users.rb:12:in `block in change' 
C:/Benutzer/Clemens/RubymineProjects/RubyAndroid/db/migrate/20160826225028_devise_create_users.rb:3:in `change' 
C:/Benutzer/Clemens/RubymineProjects/RubyAndroid/bin/rails:4:in `require' 
C:/Benutzer/Clemens/RubymineProjects/RubyAndroid/bin/rails:4:in `<top (required)>' 
-e:1:in `load' 
-e:1:in `<main>' 
ActiveRecord::StatementInvalid: Mysql2::Error: Table 'rubyandroid_development.users' doesn't exist: CREATE UNIQUE INDEX `index_users_on_authentication_token` ON `users` (`authentication_token`) 
C:/Benutzer/Clemens/RubymineProjects/RubyAndroid/db/migrate/20160826225028_devise_create_users.rb:12:in `block in change' 
C:/Benutzer/Clemens/RubymineProjects/RubyAndroid/db/migrate/20160826225028_devise_create_users.rb:3:in `change' 
C:/Benutzer/Clemens/RubymineProjects/RubyAndroid/bin/rails:4:in `require' 
C:/Benutzer/Clemens/RubymineProjects/RubyAndroid/bin/rails:4:in `<top (required)>' 
-e:1:in `load' 
-e:1:in `<main>' 
Mysql2::Error: Table 'rubyandroid_development.users' doesn't exist 
C:/Benutzer/Clemens/RubymineProjects/RubyAndroid/db/migrate/20160826225028_devise_create_users.rb:12:in `block in change' 
C:/Benutzer/Clemens/RubymineProjects/RubyAndroid/db/migrate/20160826225028_devise_create_users.rb:3:in `change' 
C:/Benutzer/Clemens/RubymineProjects/RubyAndroid/bin/rails:4:in `require' 
C:/Benutzer/Clemens/RubymineProjects/RubyAndroid/bin/rails:4:in `<top (required)>' 
-e:1:in `load' 
-e:1:in `<main>' 
Tasks: TOP => db:migrate 
(See full trace by running task with --trace) 
== 20160826225028 DeviseCreateUsers: migrating ================================ 
-- create_table(:users) 
-- add_index(:users, :authentication_token, {:unique=>true}) 

Process finished with exit code 1 

ここデシベル/移行/ devise_create_usersコードは次のとおりです。ここで

class DeviseCreateUsers < ActiveRecord::Migration[5.0] 
    def change 
    create_table :users do |t| 
     ## Database authenticatable 
     t.string :email,    null: false, default: "" 
     t.string :encrypted_password, null: false, default: "" 

     t.string :name, :null => false, :default => "" 

     #token hinzugefügt 
     t.string :authentication_token 
     add_index :users, :authentication_token, :unique => true 


     ## Recoverable 
     t.string :reset_password_token 
     t.datetime :reset_password_sent_at 

     ## Rememberable 
     t.datetime :remember_created_at 

     ## Trackable 
     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 

     ## Confirmable 
     # t.string :confirmation_token 
     # t.datetime :confirmed_at 
     # t.datetime :confirmation_sent_at 
     # t.string :unconfirmed_email # Only if using reconfirmable 

     ## Lockable 
     # t.integer :failed_attempts, default: 0, null: false # Only if lock strategy is :failed_attempts 
     # t.string :unlock_token # Only if unlock strategy is :email or :both 
     # t.datetime :locked_at 


     t.timestamps null: false 
    end 

    add_index :users, :email,    unique: true 
    add_index :users, :reset_password_token, unique: true 
    # add_index :users, :confirmation_token, unique: true 
    # add_index :users, :unlock_token,   unique: true 
    end 
end 

はデシベル/移行add_devise_to_users

class AddDeviseToUsers < ActiveRecord::Migration[5.0] 
    def self.up 
    change_table :users do |t| 
     ## Database authenticatable 
     t.string :email,    null: false, default: "" 
     t.string :encrypted_password, null: false, default: "" 

     ## Recoverable 
     t.string :reset_password_token 
     t.datetime :reset_password_sent_at 

     ## Rememberable 
     t.datetime :remember_created_at 

     ## Trackable 
     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 

     ## Confirmable 
     # t.string :confirmation_token 
     # t.datetime :confirmed_at 
     # t.datetime :confirmation_sent_at 
     # t.string :unconfirmed_email # Only if using reconfirmable 

     ## Lockable 
     # t.integer :failed_attempts, default: 0, null: false # Only if lock strategy is :failed_attempts 
     # t.string :unlock_token # Only if unlock strategy is :email or :both 
     # t.datetime :locked_at 


     # Uncomment below if timestamps were not included in your original model. 
     # t.timestamps null: false 
    end 

    add_index :users, :email,    unique: true 
    add_index :users, :reset_password_token, unique: true 
    # add_index :users, :confirmation_token, unique: true 
    # add_index :users, :unlock_token,   unique: true 
    end 

    def self.down 
    # By default, we don't want to make any assumption about how to roll back a migration when your 
    # model already existed. Please edit below which fields you would like to remove in this migration. 
    raise ActiveRecord::IrreversibleMigration 
    end 
end 

です210

UPDATE：私は行のコメントを忘れていました： add_index：users、：authentication_token、：unique => true。移行、次のエラーが発生します：私はすくいデシベル行うときしかし、今

Mysql2::Error: Duplicate column name 'email': ALTER TABLE `users` ADD `email` varchar(255) DEFAULT '' NOT NULL 
C:/Benutzer/Clemens/RubymineProjects/RubyAndroid/db/migrate/20160827004755_add_devise_to_users.rb:5:in `block in up' 
C:/Benutzer/Clemens/RubymineProjects/RubyAndroid/db/migrate/20160827004755_add_devise_to_users.rb:3:in `up' 
C:/Benutzer/Clemens/RubymineProjects/RubyAndroid/bin/rails:4:in `require' 
C:/Benutzer/Clemens/RubymineProjects/RubyAndroid/bin/rails:4:in `<top (required)>' 
-e:1:in `load' 
-e:1:in `<main>' 
ActiveRecord::StatementInvalid: Mysql2::Error: Duplicate column name 'email': ALTER TABLE `users` ADD `email` varchar(255) DEFAULT '' NOT NULL 
C:/Benutzer/Clemens/RubymineProjects/RubyAndroid/db/migrate/20160827004755_add_devise_to_users.rb:5:in `block in up' 
C:/Benutzer/Clemens/RubymineProjects/RubyAndroid/db/migrate/20160827004755_add_devise_to_users.rb:3:in `up' 
C:/Benutzer/Clemens/RubymineProjects/RubyAndroid/bin/rails:4:in `require' 
C:/Benutzer/Clemens/RubymineProjects/RubyAndroid/bin/rails:4:in `<top (required)>' 
-e:1:in `load' 
-e:1:in `<main>' 
Mysql2::Error: Duplicate column name 'email' 
C:/Benutzer/Clemens/RubymineProjects/RubyAndroid/db/migrate/20160827004755_add_devise_to_users.rb:5:in `block in up' 
C:/Benutzer/Clemens/RubymineProjects/RubyAndroid/db/migrate/20160827004755_add_devise_to_users.rb:3:in `up' 
C:/Benutzer/Clemens/RubymineProjects/RubyAndroid/bin/rails:4:in `require' 
C:/Benutzer/Clemens/RubymineProjects/RubyAndroid/bin/rails:4:in `<top (required)>' 
-e:1:in `load' 
-e:1:in `<main>' 
Tasks: TOP => db:migrate 
(See full trace by running task with --trace) 
== 20160827004755 AddDeviseToUsers: migrating ================================= 
-- change_table(:users) 

Answer 1

をあなただけの本当に最初のものを必要とする必要があるとして、あなたは、このための2つの移行ファイルを持っている理由私はわかりません。最初のものは、それはやるべきではないcreate_tableブロックに次の行

add_index :users, :authentication_token, :unique => true 

が含まれています。私はその行をそのブロックの下の行に移動することで（create_tableの外側にありますが、changeのブロック内にもう1つのadd_index行内にある）、この問題を修正する必要があります。