我尝试使用宝石安装pg,但它似乎不工作。

Gem install pg给出这个错误

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

C:/Ruby/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.

Provided configuration options:
        --with-opt-dir
        --without-opt-dir
        --with-opt-include
        --without-opt-include=${opt-dir}/include
        --with-opt-lib
        --without-opt-lib=${opt-dir}/lib
        --with-make-prog
        --without-make-prog
        --srcdir=.
        --curdir
        --ruby=C:/Ruby/bin/ruby
        --with-pg
        --without-pg
        --with-pg-dir
        --without-pg-dir
        --with-pg-include
        --without-pg-include=${pg-dir}/include
        --with-pg-lib
        --without-pg-lib=${pg-dir}/lib
        --with-pg-config
        --without-pg-config
        --with-pg_config
        --without-pg_config


Gem files will remain installed in C:/Ruby/lib/ruby/gems/1.8/gems/pg-0.10.1 for
inspection.
Results logged to C:/Ruby/lib/ruby/gems/1.8/gems/pg-0.10.1/ext/gem_make.out

当前回答

Mac用户

PATH=$PATH:/Library/PostgreSQL/9.4/bin/ gem install pg

这应该能奏效

其他回答

如果你正在使用Postgres。在Mac上的应用程序,你可以解决这个问题一劳永逸,像这样:

首先gem卸载pg,然后编辑~/。Bash_profile或~/。ZSHRC文件或同等文件,并添加:

# PostgreSQL bin path
export PATH=$PATH:/Applications/Postgres.app/Contents/Versions/9.4/bin

然后bundle install和gem install pg都可以正常工作。

Ubuntu 20.10 (pop!_os) Ruby 2.7.2 Rails 3.1.0 Postgresql 12

卸载后重新安装postgresql-client libpq5 libpq-dev

sudo apt remove postgresql-client libpq5 libpq-dev
sudo apt install postgresql-client libpq5 libpq-dev

然后再次安装pg gem,指向/usr/lib,找到pg库:

gem install pg  --   --with-pg-lib=/usr/lib

输出(你应该在前面的命令之后看到的):

Building native extensions with: '--with-pg-lib=/usr/lib'
This could take a while...
Successfully installed pg-1.2.3
Parsing documentation for pg-1.2.3
Installing ri documentation for pg-1.2.3
Done installing documentation for pg after 1 seconds
1 gem installed

Gem应该安装,然后继续正常的bundle安装或更新:

bundle
bundle install
bundle update

我在Linux Mint (Maya) 13上解决了这个问题,我通过安装postgresql和postgresql-server来修复它:

apt-get install postgresql-9.1 

sudo apt-get install postgresql-server-dev-9.1

你只要到这里看看你的pg版本是否支持Win32平台,然后使用这个命令来安装:

Gem install pg -v 0.14.1——platform=x86-mingw32

在macOS (El Capitan)上。你可以简单使用:brew install postgresql