Question

我想在我的应用程序上运行我在heroku上的迁移，但是我收到了这个错误：

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 <top (required)> 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 <top (required)> 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 <top (required)> 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

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

Answer 1

看起来如下：

20120525005302_create_users.rb将尝试在您的数据库中创建users表。
20120611000411_devise_create_users.rb还将尝试在数据库中创建users表。
您的数据库当前已经有一个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：

回滚（或删除）数据库，然后再次运行迁移。（如果20120525005302_create_users.rb为空，您可以将其删除。）
修改您的20120611000411_devise_create_users.rb迁移，以便在执行任何其他操作之前删除任何现有的users表。
修改20120611000411_devise_create_users.rb迁移，如下所示：
- 不是创建users表，而是修改现有表。
- 添加和修改数据库组件以对应

通常，如果您的应用程序处于“婴儿状态”，那么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，则需要保留该数据并继续修改20120611000411_devise_create_users.rb迁移以非破坏性地更改数据库。

<强>参考

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

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

heroku运行rake db：迁移错误

2 个答案: