ruby-on-rails - ruby rails : Bad connection with PG after running rake:db migrate

Question

最近我 fork 并克隆了一个我正在贡献的 repo，当我运行 rails s 时我没有得到任何错误，但是当我运行 rake db:migrate 时我得到了这个.

    rake aborted!
PG::ConnectionBad: could not connect to server: No such file or directory
    Is the server running locally and accepting
    connections on Unix domain socket "/tmp/.s.PGSQL.5432"?
/Users/taimurknaziri/.rvm/gems/ruby-2.1.1/gems/activerecord-4.1.4/lib/active_record/connection_adapters/postgresql_adapter.rb:888:in `initialize'
/Users/taimurknaziri/.rvm/gems/ruby-2.1.1/gems/activerecord-4.1.4/lib/active_record/connection_adapters/postgresql_adapter.rb:888:in `new'
/Users/taimurknaziri/.rvm/gems/ruby-2.1.1/gems/activerecord-4.1.4/lib/active_record/connection_adapters/postgresql_adapter.rb:888:in `connect'
/Users/taimurknaziri/.rvm/gems/ruby-2.1.1/gems/activerecord-4.1.4/lib/active_record/connection_adapters/postgresql_adapter.rb:568:in `initialize'
/Users/taimurknaziri/.rvm/gems/ruby-2.1.1/gems/activerecord-4.1.4/lib/active_record/connection_adapters/postgresql_adapter.rb:41:in `new'
/Users/taimurknaziri/.rvm/gems/ruby-2.1.1/gems/activerecord-4.1.4/lib/active_record/connection_adapters/postgresql_adapter.rb:41:in `postgresql_connection'
/Users/taimurknaziri/.rvm/gems/ruby-2.1.1/gems/activerecord-4.1.4/lib/active_record/connection_adapters/abstract/connection_pool.rb:435:in `new_connection'
/Users/taimurknaziri/.rvm/gems/ruby-2.1.1/gems/activerecord-4.1.4/lib/active_record/connection_adapters/abstract/connection_pool.rb:445:in `checkout_new_connection'
/Users/taimurknaziri/.rvm/gems/ruby-2.1.1/gems/activerecord-4.1.4/lib/active_record/connection_adapters/abstract/connection_pool.rb:416:in `acquire_connection'
/Users/taimurknaziri/.rvm/gems/ruby-2.1.1/gems/activerecord-4.1.4/lib/active_record/connection_adapters/abstract/connection_pool.rb:351:in `block in checkout'
/Users/taimurknaziri/.rvm/gems/ruby-2.1.1/gems/activerecord-4.1.4/lib/active_record/connection_adapters/abstract/connection_pool.rb:350:in `checkout'
/Users/taimurknaziri/.rvm/gems/ruby-2.1.1/gems/activerecord-4.1.4/lib/active_record/connection_adapters/abstract/connection_pool.rb:265:in `block in connection'
/Users/taimurknaziri/.rvm/gems/ruby-2.1.1/gems/activerecord-4.1.4/lib/active_record/connection_adapters/abstract/connection_pool.rb:264:in `connection'
/Users/taimurknaziri/.rvm/gems/ruby-2.1.1/gems/activerecord-4.1.4/lib/active_record/connection_adapters/abstract/connection_pool.rb:541:in `retrieve_connection'
/Users/taimurknaziri/.rvm/gems/ruby-2.1.1/gems/activerecord-4.1.4/lib/active_record/connection_handling.rb:113:in `retrieve_connection'
/Users/taimurknaziri/.rvm/gems/ruby-2.1.1/gems/activerecord-4.1.4/lib/active_record/connection_handling.rb:87:in `connection'
/Users/taimurknaziri/.rvm/gems/ruby-2.1.1/gems/activerecord-4.1.4/lib/active_record/migration.rb:910:in `initialize'
/Users/taimurknaziri/.rvm/gems/ruby-2.1.1/gems/activerecord-4.1.4/lib/active_record/migration.rb:807:in `new'
/Users/taimurknaziri/.rvm/gems/ruby-2.1.1/gems/activerecord-4.1.4/lib/active_record/migration.rb:807:in `up'
/Users/taimurknaziri/.rvm/gems/ruby-2.1.1/gems/activerecord-4.1.4/lib/active_record/migration.rb:785:in `migrate'
/Users/taimurknaziri/.rvm/gems/ruby-2.1.1/gems/activerecord-4.1.4/lib/active_record/railties/databases.rake:34:in `block (2 levels) in <top (required)>'
/Users/taimurknaziri/.rvm/gems/ruby-2.1.1/bin/ruby_executable_hooks:15:in `eval'
/Users/taimurknaziri/.rvm/gems/ruby-2.1.1/bin/ruby_executable_hooks:15:in `<main>'
Tasks: TOP => db:migrate
(See full trace by running task with --trace)

我和其他有同样问题的人一起检查了一些其他线程，但是他们的解决方案对我来说真的没有任何运气。

我尝试卸载并重新安装 PG 以及删除 .PID 文件，但我似乎没有。

有什么线索、指示或建议吗？提前致谢。

Answer 1

这意味着 config/ 目录中的 database.yml 文件未针对您的环境正确设置，很可能是 development是默认值，或者您没有运行 postgresql。

如果您没有运行postgresql，请安装或启动它。您可以检查 postgresql，很可能使用以下任一方法:

sudo service postgresql status

或者 ps-ef | grep postgres

如果你确实有 postgresql 正在运行，那么检查你的 database.yml 文件并适本地编辑它，很可能是这样的:

development:
  adapter: postgresql
  encoding: unicode
  database: database_name
  host: localhost
  username: user_name
  password: password