Ruby on Rails 中的 MySQL 数据库连接问题

Question

在学习教程时，我在运行 rails server 时遇到错误

在 ruby​​gems 存储库中找不到 gem 'mysql2 (~> 0.5)' https://rubygems.org/ 或本地安装。来源不 包含任何版本的“mysql2” 运行 bundle install 来安装缺失的 gem。

后来我运行了建议的命令，但又遇到了错误

Installing mysql2 0.5.3 with native extensions
Gem::Ext::BuildError: ERROR: Failed to build gem native extension.

current directory:
C:/Ruby30-x64/lib/ruby/gems/3.0.0/gems/mysql2-0.5.3/ext/mysql2
C:/Ruby30-x64/bin/ruby.exe -I C:/Ruby30-x64/lib/ruby/3.0.0 -r
./siteconf20210723-9416-we9bmo.rb extconf.rb
checking for rb_absint_size()... yes
checking for rb_absint_singlebit_p()... yes
checking for rb_wait_for_single_fd()... yes
*** 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:/Ruby30-x64/bin/$(RUBY_BASE_NAME)
        --with-mysql-dir
        --without-mysql-dir
        --with-mysql-include
        --without-mysql-include=${mysql-dir}/include
        --with-mysql-lib
        --without-mysql-lib=${mysql-dir}/lib
        --with-mysql-config
        --without-mysql-config
        --with-mysqlclient-dir
        --without-mysqlclient-dir
        --with-mysqlclient-include
        --without-mysqlclient-include=${mysqlclient-dir}/include
        --with-mysqlclient-lib
        --without-mysqlclient-lib=${mysqlclient-dir}/lib
        --with-mysqlclientlib
        --without-mysqlclientlib
C:/Ruby30-x64/lib/ruby/3.0.0/mkmf.rb:1050:in `block in find_library': undefined
method `split' for nil:NilClass (NoMethodError)
        from C:/Ruby30-x64/lib/ruby/3.0.0/mkmf.rb:1050:in `collect'
        from C:/Ruby30-x64/lib/ruby/3.0.0/mkmf.rb:1050:in `find_library'
        from extconf.rb:87:in `<main>'

To see why this extension failed to compile, please check the mkmf.log which can
be found here:

C:/Ruby30-x64/lib/ruby/gems/3.0.0/extensions/x64-mingw32/3.0.0/mysql2-0.5.3/mkmf.log

extconf failed, exit code 1

Gem files will remain installed in
C:/Ruby30-x64/lib/ruby/gems/3.0.0/gems/mysql2-0.5.3 for inspection.
Results logged to
C:/Ruby30-x64/lib/ruby/gems/3.0.0/extensions/x64-mingw32/3.0.0/mysql2-0.5.3/gem_make.out

An error occurred while installing mysql2 (0.5.3), and Bundler cannot continue.
Make sure that `gem install mysql2 -v '0.5.3' --source 'https://rubygems.org/'`
succeeds before bundling.

In Gemfile:
  mysql2

如果有人能帮我解决这个问题，我将不胜感激， 谢谢。

Answer 1

试试下面的命令

sudo apt-get install ruby-dev

sudo apt-get install libmysqlclient-dev

sudo gem install mysql2