heroku运行rake db：迁移错误

我想在我的应用程序上运行我在heroku上的迁移，但是我收到此错误：

Running `rake db:migrate` attached to terminal... up, run.1 DEPRECATION WARNING: You have Rails 2.3-style plugins in vendor/plugins! Support for these plugins will be removed in Rails 4.0. Move them out and bundle them in your Gemfile, or fold them in to your app as lib/myplugin/* and config/initializers/myplugin.rb. See the release notes for more on this: http://weblog.rubyonrails.org/2012/1/4/rails-3-2-0-rc2-has-been-released. (called from  at /app/Rakefile:7) DEPRECATION WARNING: You have Rails 2.3-style plugins in vendor/plugins! Support for these plugins will be removed in Rails 4.0. Move them out and bundle them in your Gemfile, or fold them in to your app as lib/myplugin/* and config/initializers/myplugin.rb. See the release notes for more on this: http://weblog.rubyonrails.org/2012/1/4/rails-3-2-0-rc2-has-been-released. (called from  at /app/Rakefile:7) DEPRECATION WARNING: You have Rails 2.3-style plugins in vendor/plugins! Support for these plugins will be removed in Rails 4.0. Move them out and bundle them in your Gemfile, or fold them in to your app as lib/myplugin/* and config/initializers/myplugin.rb. See the release notes for more on this: http://weblog.rubyonrails.org/2012/1/4/rails-3-2-0-rc2-has-been-released. (called from  at /app/Rakefile:7) Migrating to CreateUsers (20120525005302) Migrating to DeviseCreateUsers (20120611000411) == DeviseCreateUsers: migrating ============================================== -- create_table(:users) rake aborted! An error has occurred, this and all later migrations canceled: PGError: ERROR: relation "users" already exists : CREATE TABLE "users" ("id" serial primary key, "email" character varying(255) DEFAULT '' NOT NULL, "encrypted_password" character varying(255) DEFAULT '' NOT NULL, "reset_password_token" character varying(255), "reset_password_sent_at" timestamp, "remember_created_at" timestamp, "sign_in_count" integer DEFAULT 0, "current_sign_in_at" timestamp, "last_sign_in_at" timestamp, "current_sign_in_ip" character varying(255), "last_sign_in_ip" character varying(255), "created_at" timestamp NOT NULL, "updated_at" timestamp NOT NULL) Tasks: TOP => db:migrate 

我的github存储库中有以下迁移文件

1. 20120525005302_create_users.rb（这是空的，不知道如何删除它）
2. 20120611000411_devise_create_users.rb
3. 20120613140535_create_authentications.rb

Answer 1

看起来如下：

• 20120525005302_create_users.rb将尝试在数据库中创建users表。
• 20120611000411_devise_create_users.rb还将尝试在数据库中创建users表。
• 您的数据库当前已有一个users表，因此迁移在第二次迁移时失败。

要使数据库中的users表与20120611000411_devise_create_users.rb迁移正确对应，您可以执行以下两项操作之一：

1. 回滚（或删除）数据库，然后再次运行迁移。 （如果它为空，您可以删除20120525005302_create_users.rb 。）
2. 在执行任何其他操作之前，请修改20120611000411_devise_create_users.rb迁移以删除任何现有users表。
3. 修改您的20120611000411_devise_create_users.rb迁移，如下所示：
   • 而不是创建users表，修改现有表。
   • 添加和修改数据库组件以进行对应

通常，如果您的应用程序处于“婴儿状态”，则重新创建数据库往往是构建应用程序初始结构的快速方法。 但是，如果您的users表中已有重要数据，则需要保留该数据，然后通过修改20120611000411_devise_create_users.rb迁移来非破坏性地更改数据库。

参考

• 在Heroku上运行Rake命令
• RailsGuides：迁移

Answer 2

看起来你已经有了table_create_users尝试重新创建的表用户（可能来自create_users migration）

您可以修改create_device_users迁移，只需添加所需的字段即可

或者，如果它是一个没有用户的全新应用程序，您可以放弃并尝试重新运行所有迁移