“ActiveRecord::PendingMigrationError 迁移正在挂起”错误是什么意思？

Question

我收到此错误：

ActiveRecord::PendingMigrationError 迁移正在挂起。要解决此问题，请运行： bin/rake db:migrate RAILS_ENV=development

提取的源代码（围绕第 392 行）：390 391 def check_pending!(connection = Base.connection) 392 引发 ActiveRecord::PendingMigrationError 如果 ActiveRecord::Migrator.needs_migration?(connection) 393 end 394 395 def load_schema_if_pending！

Rails.root：/Users/checkkdahustle/Desktop/Full Sail/25。高级服务器端语言/ASL/APP_2/Project2/ShoeDeals

应用程序跟踪 | 框架跟踪 | 完整跟踪 activerecord (4.2.5) lib/active_record/migration.rb:392:in check_pending!' activerecord (4.2.5) lib/active_record/migration.rb:373:incall' actionpack (4.2.5) lib/action_dispatch/middleware/callbacks.rb:29:in block in call' activesupport (4.2.5) lib/active_support/callbacks.rb:88:in run_callbacks ' activesupport (4.2.5) lib/ active_support/callbacks.rb:778:in _run_call_callbacks' activesupport (4.2.5) lib/active_support/callbacks.rb:81:in run_callbacks' actionpack (4.2.5) lib/action_dispatch/middleware/callbacks.rb:27:in call' actionpack (4.2.5) lib/action_dispatch/middleware/reloader.rb:73:incall' actionpack (4.2.5) lib/action_dispatch/middleware/remote_ip.rb:78:在 call' actionpack (4.2.5) lib/action_dispatch/middleware/debug_exceptions.rb:17:in通话中'web-console (2.2.1) lib/web_console/middleware.rb:39:in call' actionpack (4.2.5) lib/action_dispatch/middleware/show_exceptions.rb:30:incall' railties (4.2.5) lib/rails/rack/logger.rb:38:in call_app' railties (4.2.5) lib/rails/rack/logger.rb:20:inblock in call' activesupport (4.2) .5) lib/active_support/tagged_logging.rb:68:inblock in tagged' activesupport (4.2.5) lib/active_support/tagged_logging.rb:26:in 标记的'activesupport (4.2.5) lib/active_support/tagged_logging.rb:68:intagged' railties (4.2.5) lib/rails/rack/logger.rb:20:in调用'actionpack (4.2.5) lib/action_dispatch/middleware/request_id.rb:21:in call' rack (1.6.4) lib/rack/methodoverride.rb:22:incall' rack (1.6.4) lib/rack/runtime.rb:18:in call' activesupport (4.2.5) lib/active_support/cache/strategy/local_cache_middleware.rb:28:in call' rack (1.6.4) lib/架/ lock.rb：17：在call' actionpack (4.2.5) lib/action_dispatch/middleware/static.rb:116:in呼叫'机架（1.6.4）LIB /架/ sendfile.rb：113：在call' railties (4.2.5) lib/rails/engine.rb:518:in呼叫' railties（4.2.5）LIB /导轨/ application.rb中：165：在call' rack (1.6.4) lib/rack/lock.rb:17:in呼叫”机架(1.6.4) lib/rack/content_length.rb:15:in call' rack (1.6.4) lib/rack/handler/webrick.rb:88:inservice' /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/webrick/httpserver.rb:138 :in service' /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/webrick/httpserver.rb:94:in run' /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/webrick/server.rb:295:in `block in start_thread'

Answer 1

查看您发布的跟踪的第一行：

ActiveRecord::PendingMigrationError Migrations are pending. To resolve this issue, run: bin/rake db:migrate RAILS_ENV=development

这正是它的意思：

迁移待定

因此，您有一些尚未运行的迁移，这意味着您的架构不是最新的。

要修复它，您所要做的就是运行挂起的迁移

bundle exec rake db:migrate

如果您已经创建了数据库并且它之前正在运行。如果这是您机器上的新应用程序，则该数据库尚不存在。您必须首先创建一个数据库，然后按如下方式运行迁移：

bundle exec rake db:create db:migrate