Ruby on rails Ruby无法连接到postgresql

我已经为我的postgresql数据库编辑了database.yml，并下载了pg gem和相关库。我在谷歌上搜索了它，并以这种方式进行编辑。。但运行服务器后，在终端窗口中显示以下错误。。。。。。。请在这方面帮助我

development:
  adapter: postgresql
  encoding: unicode
  database: my db name
  username:  user name
  password: password
  host: host name

test:
  adapter: postgresql
  database: db_pchamara
  database: my db name
  username:  user name
  password: password
  host: host name
  pool: 5


production:
  adapter: postgresql
  database: my db name
  username:  user name
  password: password
  host: host name
  pool: 5

但是如果我在终端中运行命令“rails服务器”，它会显示以下错误。

Started GET "/assets/rails.png" for 127.0.0.1 at 2012-12-05 18:10:51 +0530

ActiveRecord::ConnectionNotEstablished (ActiveRecord::ConnectionNotEstablished):
  activerecord (3.2.9) lib/active_record/connection_adapters/abstract/connection_pool.rb:410:in `retrieve_connection'
  activerecord (3.2.9) lib/active_record/connection_adapters/abstract/connection_specification.rb:171:in `retrieve_connection'
  activerecord (3.2.9) lib/active_record/connection_adapters/abstract/connection_specification.rb:145:in `connection'
  activerecord (3.2.9) lib/active_record/query_cache.rb:67:in `rescue in call'
  activerecord (3.2.9) lib/active_record/query_cache.rb:61:in `call'
  activerecord (3.2.9) lib/active_record/connection_adapters/abstract/connection_pool.rb:479:in `call'
  actionpack (3.2.9) lib/action_dispatch/middleware/callbacks.rb:28:in `block in call'
  activesupport (3.2.9) lib/active_support/callbacks.rb:405:in `_run__189673354__call__558944823__callbacks'
  activesupport (3.2.9) lib/active_support/callbacks.rb:405:in `__run_callback'
  activesupport (3.2.9) lib/active_support/callbacks.rb:385:in `_run_call_callbacks'
  activesupport (3.2.9) lib/active_support/callbacks.rb:81:in `run_callbacks'
  actionpack (3.2.9) lib/action_dispatch/middleware/callbacks.rb:27:in `call'
  actionpack (3.2.9) lib/action_dispatch/middleware/reloader.rb:65:in `call'
  actionpack (3.2.9) lib/action_dispatch/middleware/remote_ip.rb:31:in `call'
  actionpack (3.2.9) lib/action_dispatch/middleware/debug_exceptions.rb:16:in `call'
  actionpack (3.2.9) lib/action_dispatch/middleware/show_exceptions.rb:56:in `call'
  railties (3.2.9) lib/rails/rack/logger.rb:32:in `call_app'
  railties (3.2.9) lib/rails/rack/logger.rb:16:in `block in call'
  activesupport (3.2.9) lib/active_support/tagged_logging.rb:22:in `tagged'
  railties (3.2.9) lib/rails/rack/logger.rb:16:in `call'
  actionpack (3.2.9) lib/action_dispatch/middleware/request_id.rb:22:in `call'
  rack (1.4.1) lib/rack/methodoverride.rb:21:in `call'
  rack (1.4.1) lib/rack/runtime.rb:17:in `call'
  activesupport (3.2.9) lib/active_support/cache/strategy/local_cache.rb:72:in `call'
  rack (1.4.1) lib/rack/lock.rb:15:in `call'
  actionpack (3.2.9) lib/action_dispatch/middleware/static.rb:62:in `call'
  railties (3.2.9) lib/rails/engine.rb:479:in `call'
  railties (3.2.9) lib/rails/application.rb:223:in `call'
  rack (1.4.1) lib/rack/content_length.rb:14:in `call'
  railties (3.2.9) lib/rails/rack/log_tailer.rb:17:in `call'
  rack (1.4.1) lib/rack/handler/webrick.rb:59:in `service'
  /usr/local/rvm/rubies/ruby-1.9.3-p327/lib/ruby/1.9.1/webrick/httpserver.rb:138:in `service'
  /usr/local/rvm/rubies/ruby-1.9.3-p327/lib/ruby/1.9.1/webrick/httpserver.rb:94:in `run'
  /usr/local/rvm/rubies/ruby-1.9.3-p327/lib/ruby/1.9.1/webrick/server.rb:191:in `block in start_thread'


  Rendered /usr/local/rvm/gems/ruby-1.9.3-p327/gems/actionpack-3.2.9/lib/action_dispatch/middleware/templates/rescues/_trace.erb (1.2ms)
  Rendered /usr/local/rvm/gems/ruby-1.9.3-p327/gems/actionpack-3.2.9/lib/action_dispatch/middleware/templates/rescues/_request_and_response.erb (2.6ms)
  Rendered /usr/local/rvm/gems/ruby-1.9.3-p327/gems/actionpack-3.2.9/lib/action_dispatch/middleware/templates/rescues/diagnostics.erb within rescues/layout (13.3ms)

---

您是否在gem文件中设置了gem“pg”

检查您的gem文件，确保您评论（或删除）了gem sqlite，并确保列出了gem pg

gem 'pg'

之后，运行bundle命令（该命令将设置应用程序启动前将加载的库）：

检查文件Gemfile.lock，确保其中列出了gem pg

完成所有这些操作后，请确保在postgresql server中实际创建数据库：

bundle exec rake db:create

以防万一，运行任何挂起的迁移

bundle exec rake db:migrate

---

如果这有帮助，我的

数据库.yml

如下所示：

development:
  adapter: postgresql
  encoding: utf8
  reconnect: false
  database: kenyu_dev
  pool: 5
  username: kenyu
  password: super_secret_pass
  host: localhost

---

另外，您是否创建了该用户并为其授予了正确的权限？尝试以用户身份登录，并使用

psql

尝试使用psql连接数据库：

psql-h'localhost'--username'user\u name''database\u name'

。如果有效，问题出在RoR上，而不是PostgreSQLyeah。。那命令很管用耶。。它在终端控制台上运行，我是数据库的超级用户。。我可以通过psql命令登录postgres。。。但是它显示了相同的错误，如果我运行命令包，它不会列出postgres gem。。我试过“捆绑秀博士后”。。但是没有用你不需要“博士后”宝石，你需要“pg”宝石。你的gem文件上有我在答案上写的gem“pg”吗？如果您这样做了，当您运行命令“bundle”时，您应该会看到类似“Using pg（0.14.1）”的内容，为了确保您拥有gem，bundle生成的文件称为“Gemfile.lock”，您可以在其中看到应用程序所依赖的所有gem。因此，您可以运行“grep pg Gemfile.lock”，您应该会看到pg gem，如果它不在那里，那么您的Gemfile出现问题，请按照我的说明重试。ThxSir我试图使用“gem install pg”安装pg gem。它运行并显示gem已成功安装，并且还创建了ri文档。。但是当我运行bundle时，它没有显示在那里，还有一件事最初我卸载了sqlite3 gem，但当我运行bundle时，sqlite3 gem会自动安装。。。先生，你能更新你的答案并删除你档案的内容吗？以防万一，在我更新问题后，删除Gemfile.lock并再次运行捆绑包。。已安装我们所需的pg gem文件…它显示在捆绑包列表中。。

development:
  adapter: postgresql
  encoding: utf8
  reconnect: false
  database: kenyu_dev
  pool: 5
  username: kenyu
  password: super_secret_pass
  host: localhost