ruby-on-rails - 发生错误，此迁移和所有后续迁移均已取消 [Rails DB 错误]

Question

提供一些背景信息:我一直在构建一个个人博客，与任何其他博客一样，它需要在数据库中进行用户身份验证(或至少一个用户)。因此，在开发过程中，我直接从 Rails 控制台创建了一个有效的用户。

但是，在生产中我需要一个身份验证系统才能创建帖子。所以我所做的就是尝试安装设备来处理这个问题，尽管我收到了如下所示的错误。

我知道这个问题与我的数据库中已经存在的用户表有关，但问题是 - 当尝试运行 rake db:migrate 来删除该表时，我收到一个错误，这最终让我处于静止状态。

请指教。

github:https://github.com/Apane/Blogit_blog

rake db:migrate
==  DeviseCreateUsers: migrating ==============================================
-- create_table(:users)
rake aborted!
An error has occurred, this and all later migrations canceled:

SQLite3::SQLException: table "users" already exists: CREATE TABLE "users" ("id" INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL, "email" varchar(255) DEFAULT '' NOT NULL, "encrypted_password" varchar(128) DEFAULT '' NOT NULL, "password_salt" varchar(255) DEFAULT '' NOT NULL, "reset_password_token" varchar(255), "remember_token" varchar(255), "remember_created_at" datetime, "sign_in_count" integer DEFAULT 0, "current_sign_in_at" datetime, "last_sign_in_at" datetime, "current_sign_in_ip" varchar(255), "last_sign_in_ip" varchar(255), "created_at" datetime NOT NULL, "updated_at" datetime NOT NULL) /usr/local/rvm/gems/ruby-1.9.3-p194/gems/sqlite3-1.3.7/lib/sqlite3/database.rb:91:in `initialize'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/sqlite3-1.3.7/lib/sqlite3/database.rb:91:in `new'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/sqlite3-1.3.7/lib/sqlite3/database.rb:91:in `prepare'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/sqlite3-1.3.7/lib/sqlite3/database.rb:134:in `execute'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.13/lib/active_record/connection_adapters/sqlite_adapter.rb:278:in `block in execute'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract_adapter.rb:280:in `block in log'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/activesupport-3.2.13/lib/active_support/notifications/instrumenter.rb:20:in `instrument'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract_adapter.rb:275:in `log'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.13/lib/active_record/connection_adapters/sqlite_adapter.rb:278:in `execute'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/schema_statements.rb:170:in `create_table'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.13/lib/active_record/migration.rb:466:in `block in method_missing'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.13/lib/active_record/migration.rb:438:in `block in say_with_time'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.13/lib/active_record/migration.rb:438:in `say_with_time'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.13/lib/active_record/migration.rb:458:in `method_missing'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.13/lib/active_record/migration.rb:334:in `method_missing'
/Users/user/Sites/personal_blog/personal_blog/db/migrate/20130528200110_devise_create_users.rb:3:in `up'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.13/lib/active_record/migration.rb:370:in `up'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.13/lib/active_record/migration.rb:410:in `block (2 levels) in migrate'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.13/lib/active_record/migration.rb:410:in `block in migrate'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/connection_pool.rb:129:in `with_connection'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.13/lib/active_record/migration.rb:389:in `migrate'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.13/lib/active_record/migration.rb:528:in `migrate'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.13/lib/active_record/migration.rb:720:in `block (2 levels) in migrate'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.13/lib/active_record/migration.rb:775:in `call'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.13/lib/active_record/migration.rb:775:in `block in ddl_transaction'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/database_statements.rb:192:in `transaction'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.13/lib/active_record/transactions.rb:208:in `transaction'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.13/lib/active_record/migration.rb:775:in `ddl_transaction'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.13/lib/active_record/migration.rb:719:in `block in migrate'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.13/lib/active_record/migration.rb:700:in `each'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.13/lib/active_record/migration.rb:700:in `migrate'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.13/lib/active_record/migration.rb:570:in `up'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.13/lib/active_record/migration.rb:551:in `migrate'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.13/lib/active_record/railties/databases.rake:193:in `block (2 levels) in <top (required)>'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/rake-10.0.4/lib/rake/task.rb:246:in `call'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/rake-10.0.4/lib/rake/task.rb:246:in `block in execute'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/rake-10.0.4/lib/rake/task.rb:241:in `each'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/rake-10.0.4/lib/rake/task.rb:241:in `execute'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/rake-10.0.4/lib/rake/task.rb:184:in `block in invoke_with_call_chain'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/rake-10.0.4/lib/rake/task.rb:177:in `invoke_with_call_chain'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/rake-10.0.4/lib/rake/task.rb:170:in `invoke'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/rake-10.0.4/lib/rake/application.rb:143:in `invoke_task'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/rake-10.0.4/lib/rake/application.rb:101:in `block (2 levels) in top_level'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/rake-10.0.4/lib/rake/application.rb:101:in `each'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/rake-10.0.4/lib/rake/application.rb:101:in `block in top_level'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/rake-10.0.4/lib/rake/application.rb:110:in `run_with_threads'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/rake-10.0.4/lib/rake/application.rb:95:in `top_level'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/rake-10.0.4/lib/rake/application.rb:73:in `block in run'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/rake-10.0.4/lib/rake/application.rb:160:in `standard_exception_handling'
/usr/local/rvm/gems/ruby-1.9.3-p194/gems/rake-10.0.4/lib/rake/application.rb:70:in `run'
Tasks: TOP => db:migrate
(See full trace by running task with --trace)

Answer 1

您的问题是在错误中指出:

rake db:migrate
==  DeviseCreateUsers: migrating ==============================================
-- create_table(:users

所以我相信发生的事情是您尝试迁移当前已经存在的 users 表。我还注意到您正在使用设备。您是否运行了以下命令:

rails g devise:install

rails g devise user

rake db:migrate

您还应该将 schema.rb 版本与 db/migrate/*.rb 文件进行比较。

更新

您确定要连接到同一个数据库吗？因为我刚刚注意到你说

in development I created a user right from the rails console which worked.

但是在生产中你遇到了问题。在我看来，您可能没有连接到同一个数据库。另外建议不要使用 SQLite3 进行生产。

请检查您在哪个环境中连接到哪个数据库。如果您要在 Heroku 上发布应用程序，这是一个很好的做法。您可能会注意到它使用 Postgres。良好的做法是使用相同的数据库进行开发和生产。

一旦你找出你正在连接的数据库以及它是什么，我确信这可能是问题所在。

此外，如果您尝试在生产环境中进行迁移或类似的操作，您可以使用以下命令:bundle exec rake db:migrate RAILS_ENV=product 这将为生产环境执行迁移