OSX 上的 rails + MySQL：库未加载：libmysqlclient.18.dylib
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rails + MySQL on OSX: Library not loaded: libmysqlclient.18.dylib
提问by George Armhold
I'm just starting out with Ruby (and rails). I did the setup according to http://ruby.railstutorial.org/ruby-on-rails-tutorial-book#sec:rubygems, using rvm. I have everything working well with sqlite.
我刚刚开始使用 Ruby（和 Rails）。我根据http://ruby.railstutorial.org/ruby-on-rails-tutorial-book#sec:rubygems进行了设置，使用rvm. 我的一切都与 sqlite 配合良好。
Now I'd like to try converting things over to MySQL, since that's what I do most of my development with. In my Gemfile I've replaced sqlite with mysql2:
现在我想尝试将事物转换为 MySQL，因为这是我进行的大部分开发工作。在我的 Gemfile 中，我用 mysql2 替换了 sqlite：
group :development, :test do
# gem 'sqlite3', '1.3.5'
gem 'mysql2'
gem 'rspec-rails', '2.9.0'
end
But when I try to create the DB for rails in MySQL I get:
但是当我尝试在 MySQL 中为 rails 创建数据库时，我得到：
$ rake db:create --trace
rake aborted!
dlopen(/Users/username/.rvm/gems/ruby-1.9.3-p194@rails3tutorial2ndEd/gems/mysql2-0.3.11/lib/mysql2/mysql2.bundle, 9): Library not loaded: libmysqlclient.18.dylib
Referenced from: /Users/username/.rvm/gems/ruby-1.9.3-p194@rails3tutorial2ndEd/gems/mysql2-0.3.11/lib/mysql2/mysql2.bundle
Reason: image not found - /Users/username/.rvm/gems/ruby-1.9.3-p194@rails3tutorial2ndEd/gems/mysql2-0.3.11/lib/mysql2/mysql2.bundle
I've seen other postings recommending re-installing MySQL via homebrew (mine was installed via a downloadable DMG), but I'd prefer not to do that as I have several other databases in there already for other non-ruby projects.
我已经看到其他帖子建议通过自制软件重新安装 MySQL（我的是通过可下载的 DMG 安装的），但我不想这样做，因为我已经有其他几个数据库用于其他非 ruby 项目。
I do in fact have the file that Rails is looking for; it's installed in /usr/local/mysql/lib/libmysqlclient.18.dylib. What's the best way to tell Rails how to locate it?
我确实有 Rails 正在寻找的文件；它安装在/usr/local/mysql/lib/libmysqlclient.18.dylib. 告诉 Rails 如何定位它的最佳方式是什么？
回答by atejeda
The solution is pretty easy; Add the library path in your ~/.bash_profile or ~/.profile file:
解决方案非常简单；在 ~/.bash_profile 或 ~/.profile 文件中添加库路径：
MYSQL=/usr/local/mysql/bin
export PATH=$PATH:$MYSQL
export DYLD_LIBRARY_PATH=/usr/local/mysql/lib:$DYLD_LIBRARY_PATH
If it is still not working (this work for me):
如果它仍然不起作用（这对我有用）：
sudo ln -s /usr/local/mysql/lib/libmysqlclient.18.dylib /usr/lib/libmysqlclient.18.dylib
There are many blogs with install_name_tool, which won't work for me because I'm on OSX Lion:
有很多博客install_name_tool，这对我不起作用，因为我使用的是 OSX Lion：
sudo install_name_tool -change libmysqlclient.18.dylib /usr/local/mysql/lib/libmysqlclient.18.dylib /usr/local/bin/indexer
sudo install_name_tool -change libmysqlclient.18.dylib /usr/local/mysql/lib/libmysqlclient.18.dylib /usr/local/bin/search
回答by TinMonkey
In El Capitan I got ln: /usr/lib/libmysqlclient.18.dylib: Operation not permitted
在 El Capitan 我得到了 ln: /usr/lib/libmysqlclient.18.dylib: Operation not permitted
In El Capitan /usr/lib/now has a restricted flag and can't be written to without disabling security so I just put the link in /usr/local/libinstead.
在 El Capitan/usr/lib/现在有一个受限制的标志，如果不禁用安全就不能写入，所以我只是把链接放在里面/usr/local/lib。
sudo ln -s /usr/local/mysql/lib/libmysqlclient.18.dylib /usr/local/lib/libmysqlclient.18.dylib
Rails server is running fine again.
Rails 服务器再次运行良好。
回答by Giuseppe
While the title of this question describes precisely the problem I encountered, the circumstances are different from those described in the previous answers, and so was the solution.
虽然这个问题的标题准确地描述了我遇到的问题，但情况与之前答案中描述的情况不同，解决方案也是如此。
In my case (El Capitan, mysql installed via homebrew), a brew update && brew upgradecaused the mysql package to be upgraded to 5.7.10 (from 5.6.x).
在我的情况下（El Capitan，mysql 通过自制软件安装），brew update && brew upgrade导致 mysql 包升级到 5.7.10（从 5.6.x）。
The upgrade caused libmysqlclient.18.dylibto be replaced with libmysqlclient.20.dylib, but the mysql2gem was still relying on the former.
升级导致libmysqlclient.18.dylib替换为libmysqlclient.20.dylib，但mysql2gem 仍然依赖于前者。
To fix the problem I did: gem uninstall mysql2 && gem install mysql2
为了解决我所做的问题： gem uninstall mysql2 && gem install mysql2
Please note that similar problems can occur with different homebrew-managed libraries (see my own answer to this, for example)
请注意，不同的自制软件管理的库可能会出现类似的问题（例如，请参阅我自己的回答）
回答by Joseph
sudo ln -s /usr/local/mysql-5.5.25-osx10.6-x86_64/lib/libmysqlclient.18.dylib /usr/lib/libmysqlclient.18.dylib
That worked for me. I installed MySQL from a dmg file.
那对我有用。我从 dmg 文件安装了 MySQL。
回答by Greg Benner
sudo ln -s /usr/local/mysql/lib/libmysqlclient.18.dylib /usr/lib/libmysqlclient.18.dylib
Worked for me. All the similar ones didn't.
为我工作。所有类似的都没有。
回答by sealocal
I ran into this problem after a complete removal and then fresh install of MySQL. Specifically:
在完全删除然后全新安装 MySQL 后，我遇到了这个问题。具体来说：
Library not loaded: /usr/local/opt/mysql/lib/libmysqlclient.20.dylib
I had not even touched my Rails app.
我什至没有接触过我的 Rails 应用程序。
Reinstalling the mysql2gem solved this problem.
重新安装mysql2gem 解决了这个问题。
$ gem uninstall mysql2
$ gem install mysql2 -v 0.3.18 # (specifying the version found in my Gemfile.lock)
[MySQL 5.7.10, Rails 4.0.0, Ruby 2.0.0, Mac OS X Yosemite 10.10]
[MySQL 5.7.10、Rails 4.0.0、Ruby 2.0.0、Mac OS X Yosemite 10.10]
回答by arjunswaj
If you are using MySQL installed from HomeBrew in El Capitan, then you should link it as follows:
如果您使用的是从 El Capitan 的 HomeBrew 安装的 MySQL，那么您应该将其链接如下：
sudo ln -sf /usr/local/Cellar/mysql/5.6.27/lib/libmysqlclient.18.dylib /usr/local/lib/libmysqlclient.18.dylib
回答by Abhishek Pande
For MySql 5.6 installed from DMG on Mavericks
对于在 Mavericks 上从 DMG 安装的 MySql 5.6
sudo ln -s /usr/local/mysql-5.6.14-osx10.7-x86_64/lib/libmysqlclient.18.dylib /usr/lib/libmysqlclient.18.dylib
回答by ingconti
I confirm patch from Abhishek doeswork.
我确认来自 Abhishek 的补丁确实有效。
it work for Yosemite, too.
它也适用于优胜美地。
note: instead of linking to a particular version of mysql, use the fact mysql already built symlink:
注意：不要链接到特定版本的 mysql，而是使用 mysql 已经构建的符号链接：
sudo ln -s /usr/local/mysql/lib/libmysqlclient.18.dylib /usr/lib/libmysqlclient.18.dylib
this solution does work for Xcode and C API.
此解决方案适用于 Xcode 和 C API。
回答by tagaism
For those who are using brew. Just link you mysql version with "--force" option.
对于那些使用 brew 的人。只需将您的 mysql 版本与“--force”选项联系起来。
brew link mysql56 --force
