Iam正在尝试建立一个rails项目，该项目具有ruby 2.2.3和rails版本4.2.7.1。它使用PostgreSQL作为数据库。我可以在GemFile中看到gem"pg"条目。我确实进行了捆绑安装来安装依赖项，但当涉及到安装pg gem时，它给了我以下错误。我的ubuntu 18.04 LTS系统上没有安装postgreSQL。这可能是我得到这个错误的原因吗。请帮忙。我得到的错误：
**
**Fetching pg 1.2.3
Installing pg 1.2.3 with native extensions
Gem::Ext::BuildError: ERROR: Failed to build gem native extension.
current directory: /home/pc-123/.rvm/gems/ruby-2.2.3/gems/pg-1.2.3/ext
/home/pc-123/.rvm/rubies/ruby-2.2.3/bin/ruby -I /home/pc-123/.rvm/rubies/ruby-2.2.3/lib/ruby/site_ruby/2.2.0 -r ./siteconf20200822-841-6si3xn.rb
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=/home/pc-123/.rvm/rubies/ruby-2.2.3/bin/$(RUBY_BASE_NAME)
--with-pg
--without-pg
--enable-windows-cross
--disable-windows-cross
--with-pg-config
--without-pg-config
--with-pg_config
--without-pg_config
--with-pg-dir
--without-pg-dir
--with-pg-include
--without-pg-include=${pg-dir}/include
--with-pg-lib
--without-pg-lib=${pg-dir}/lib
**
您必须安装libpq-dev软件包。你正在使用Ubuntu所以：
sudo apt install libpq-dev
最好安装PostGreSQL。
这取决于您的解释器使用的Ruby版本。如果不匹配，你可能会遇到问题。使用相同的版本将解决您的问题。