Question

I am using rails 3.2.9 and database of postgres.

I have edited database.yml file in the following way and also gem pg was also installed..

When I run bundle command it shows pg gem in that list. But if I run the rails server command it shows the active connection not established.

    development:
      adapter: postgresql
      database: db_pchamara/development.postgresql
      pool: 5
      username: database username
      password: password
      host: database ip address
    
    test:
      adapter: postgresql
      database: database name/test.postgresql
      pool: 5
      username:database username
      password: password
    
    production:
      adapter: postgresql
      database: database name/production.postgresql
      pool: 5
      username: database username
      password: password

But when I run command rails server it shows as follows:

[root@vdimc04 my_app]# rails server
=> Booting WEBrick
=> Rails 3.2.9 application starting in development on http
=> Call with -d to detach
=> Ctrl-C to shutdown server
[2012-12-06 12:49:35] INFO  WEBrick 1.3.1
[2012-12-06 12:49:35] INFO  ruby 1.9.3 (2012-11-10) [i686-linux]
[2012-12-06 12:49:35] INFO  WEBrick::HTTPServer#start: pid=7536 port=3000


Started GET "/assets/rails.png" for 127.0.0.1 at 2012-12-06 12:49:53 +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__626989987__call__446659449__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 (1.3ms)
  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 (3.0ms)
  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 (29.4ms)

    
Please help me to solve this problem.

Answer 1

The problem is in the configuration of the file:

development:
  adapter: postgresql
  database: db_pchamara/development.postgresql
  pool: 5
  username: database username
  password: password
  host: database ip address

change it to:

development:
  adapter: postgresql
  database: name_of_database
  pool: 5
  username: db_user
  password: db_pass
  host: db_host

most of the time db_host is just localhost

also, make sure you can connect with psql before you actually try to connect with rails.

if the db doesn’t exist, you have to create the db with

rake db:create

cheers 😉