rails中的活动记录postgresql适配器错误

Question

Here's my problem. I am trying to create a blog. I run 'rails new blog'. Everythign is OK until I try 'rake db:create'. It returns an error:

rake aborted!
Please install the postgresql adapter: `gem install activerecord-postgresql-adap
ter` (pg is not part of the bundle. Add it to Gemfile.)

When I try to install pg adapter I get this:

Temporarily enhancing PATH to include DevKit...
Building native extensions.  This could take a while...
ERROR:  Error installing activerecord-postgresql-adapter:
    ERROR: Failed to build gem native extension.

F:/Ruby200-x64/bin/ruby.exe extconf.rb
checking for pg_config... no
No pg_config... trying anyway. If building fails, please try again with
 --with-pg-config=/path/to/pg_config
 checking for libpq-fe.h... no
Can't find the 'libpq-fe.h header
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of necessary
libraries and/or headers.  Check the mkmf.log file for more details.  You may

need configuration options.

My gemfile:

  source 'https://rubygems.org'

gem 'rails', '3.2.12'

# Bundle edge Rails instead:
# gem 'rails', :git => 'git://github.com/rails/rails.git'

gem "pg"

# Gems used only for assets and not required
# in production environments by default.
 group :assets do
  gem 'sass-rails',   '~> 3.2.3'
  gem 'coffee-rails', '~> 3.2.1'

  # See https://github.com/sstephenson/execjs#readme for more supported runtimes
  # gem 'therubyracer', :platforms => :ruby

  gem 'uglifier', '>= 1.0.3'
end

gem 'jquery-rails'

# To use ActiveModel has_secure_password
# gem 'bcrypt-ruby', '~> 3.0.0'

# To use Jbuilder templates for JSON
# gem 'jbuilder'

# Use unicorn as the app server
# gem 'unicorn'

# Deploy with Capistrano
# gem 'capistrano'

# To use debugger
# gem 'debugger'

Got any idea?

Answer 1

Do you have Postgres installed? If so, make sure that pg_config.exe is in the PATH. Alternatively use either --with-pg-config or –with-pg-dir key:

gem install pg --with-pg-config=<path>

See details in https://github.com/ged/ruby-pg/blob/master/README-Windows.rdoc

Answer 2

Uninstall pg gem, and install postgres-pr for windows

Remove from Gemfile:

gem "pg"

and put:

gem "postgres-pr"

and run:

bundle install or gem install postgres-pr or however you are installing gems

Answer 3

You are missing the library for postgresql. You can install it like this:

sudo apt-get install libpq-dev

Maybe also take a look at this old question .

Answer 4

I got the same error and I solved by setting correct file permissions to postgresql_adapter.rb

cd [YOUR_ACTIVERECORD_GEM_PATH]/lib/active_record/connection_adapters
chmod 644 postgresql_adapter.rb

---

Somehow the file permissions of postgresql_adapter.rb were corrupted in my computer...