Ruby on Rails的新錯誤應用程序數據庫未知

Question

我已經安裝了與MySQL的路徑上的紅寶石。

我mysql安裝使用命令

sudo apt-get install mysql-server 

一個PROMT出現要求輸入密碼，我將它設置爲1234，並再次PROMT確認出現的密碼。

我也安裝使用

gem install mysql2 

的mysql2寶石和創建使用

rails new app -d mysql 

新的應用程序已成功創建一個新的Rails應用程序，但是當我啓動服務器rails server和開放http://localhost:3000的發生錯誤：

unknown database 

整體stacktrace在下面給出

mysql2 (0.3.14) lib/mysql2/client.rb:67:in `connect' 
mysql2 (0.3.14) lib/mysql2/client.rb:67:in `initialize' 
activerecord (4.0.0) lib/active_record/connection_adapters/mysql2_adapter.rb:18:in `new' 
activerecord (4.0.0) lib/active_record/connection_adapters/mysql2_adapter.rb:18:in `mysql2_connection' 
activerecord (4.0.0) lib/active_record/connection_adapters/abstract/connection_pool.rb:440:in `new_connection' 
activerecord (4.0.0) lib/active_record/connection_adapters/abstract/connection_pool.rb:450:in `checkout_new_connection' 
activerecord (4.0.0) lib/active_record/connection_adapters/abstract/connection_pool.rb:421:in `acquire_connection' 
activerecord (4.0.0) lib/active_record/connection_adapters/abstract/connection_pool.rb:356:in `block in checkout' 
/home/sana/.rvm/rubies/ruby-2.0.0-p353/lib/ruby/2.0.0/monitor.rb:211:in `mon_synchronize' 
activerecord (4.0.0) lib/active_record/connection_adapters/abstract/connection_pool.rb:355:in `checkout' 
activerecord (4.0.0) lib/active_record/connection_adapters/abstract/connection_pool.rb:265:in `block in connection' 
/home/sana/.rvm/rubies/ruby-2.0.0-p353/lib/ruby/2.0.0/monitor.rb:211:in `mon_synchronize' 
activerecord (4.0.0) lib/active_record/connection_adapters/abstract/connection_pool.rb:264:in `connection' 
activerecord (4.0.0) lib/active_record/connection_adapters/abstract/connection_pool.rb:546:in `retrieve_connection' 
activerecord (4.0.0) lib/active_record/connection_handling.rb:79:in `retrieve_connection' 
activerecord (4.0.0) lib/active_record/connection_handling.rb:53:in `connection' 
activerecord (4.0.0) lib/active_record/query_cache.rb:51:in `restore_query_cache_settings' 
activerecord (4.0.0) lib/active_record/query_cache.rb:43:in `rescue in call' 
activerecord (4.0.0) lib/active_record/query_cache.rb:32:in `call' 
activerecord (4.0.0) lib/active_record/connection_adapters/abstract/connection_pool.rb:626:in `call' 
activerecord (4.0.0) lib/active_record/migration.rb:369:in `call' 
actionpack (4.0.0) lib/action_dispatch/middleware/callbacks.rb:29:in `block in call' 
activesupport (4.0.0) lib/active_support/callbacks.rb:373:in `_run__695031866633904995__call__callbacks' 
activesupport (4.0.0) lib/active_support/callbacks.rb:80:in `run_callbacks' 
actionpack (4.0.0) lib/action_dispatch/middleware/callbacks.rb:27:in `call' 
actionpack (4.0.0) lib/action_dispatch/middleware/reloader.rb:64:in `call' 
actionpack (4.0.0) lib/action_dispatch/middleware/remote_ip.rb:76:in `call' 
actionpack (4.0.0) lib/action_dispatch/middleware/debug_exceptions.rb:17:in `call' 
actionpack (4.0.0) lib/action_dispatch/middleware/show_exceptions.rb:30:in `call' 
railties (4.0.0) lib/rails/rack/logger.rb:38:in `call_app' 
railties (4.0.0) lib/rails/rack/logger.rb:21:in `block in call' 
activesupport (4.0.0) lib/active_support/tagged_logging.rb:67:in `block in tagged' 
activesupport (4.0.0) lib/active_support/tagged_logging.rb:25:in `tagged' 
activesupport (4.0.0) lib/active_support/tagged_logging.rb:67:in `tagged' 
railties (4.0.0) lib/rails/rack/logger.rb:21:in `call' 
actionpack (4.0.0) lib/action_dispatch/middleware/request_id.rb:21:in `call' 
rack (1.5.2) lib/rack/methodoverride.rb:21:in `call' 
rack (1.5.2) lib/rack/runtime.rb:17:in `call' 
activesupport (4.0.0) lib/active_support/cache/strategy/local_cache.rb:83:in `call' 
rack (1.5.2) lib/rack/lock.rb:17:in `call' 
actionpack (4.0.0) lib/action_dispatch/middleware/static.rb:64:in `call' 
railties (4.0.0) lib/rails/engine.rb:511:in `call' 
railties (4.0.0) lib/rails/application.rb:97:in `call' 
rack (1.5.2) lib/rack/lock.rb:17:in `call' 
rack (1.5.2) lib/rack/content_length.rb:14:in `call' 
rack (1.5.2) lib/rack/handler/webrick.rb:60:in `service' 
/home/sana/.rvm/rubies/ruby-2.0.0-p353/lib/ruby/2.0.0/webrick/httpserver.rb:138:in `service' 
/home/sana/.rvm/rubies/ruby-2.0.0-p353/lib/ruby/2.0.0/webrick/httpserver.rb:94:in `run' 
/home/sana/.rvm/rubies/ruby-2.0.0-p353/lib/ruby/2.0.0/webrick/server.rb:295:in `block in start_thread' 

哪裏出錯？

config/database.yml

development: 
    adapter: mysql2 
    encoding: utf8 
    database: mysqltestapp_development 
    pool: 5 
    username: root 
    password: 1234 
    host: 127.0.0.1 
    socket: /var/run/mysqld/mysqld.sock 

Answer 1

假設錯誤消息是類似於

錯誤的東西發生未知的數據庫

這意味着該數據庫不存在。確保你在MySQL中創建它（Rails不會自動創建它）。

mysql -e 'create database mysqltestapp_development;' 

如果應用程序不是新的，您還應該加載架構。

rake db:schema:load