我将我的数据库的pg gem更新为1.0.0版本，现在遇到了问题。我试图恢复到以前的版本，但仍然出现错误。有其他人有同样的问题吗？
的Gemfile
# Use postgresql as the database for Active Record
gem 'pg', '~> 0.21.0'
运行rake db:migrate
dyld: lazy symbol binding failed: Symbol not found: _rb_fd_init
Referenced from: /Users/topher/.rvm/gems/ruby-2.5.0/gems/pg-0.21.0/lib/pg_ext.bundle
Expected in: flat namespace
运行rails s
当我将我的Gemfile更改为最新版本的pg gem时，我会收到以下错误：
的Gemfile
# Use postgresql as the database for Active Record
gem 'pg', '~> 1.0.0'
运行rake db:migrate
rake aborted!
Gem::LoadError: Specified 'postgresql' for database adapter,
but the gem is not loaded. Add `gem 'pg'` to your Gemfile
(and ensure its version is at the minimum required by
ActiveRecord).
运行rails s
Specified 'postgresql' for database adapter, but the gem is not
loaded. Add `gem 'pg'` to your Gemfile (and ensure its version is
at the minimum required by ActiveRecord). (Gem::LoadError)
其他人遇到此问题并进行修复？
答案 0 :(得分：1)
在进一步研究这个问题并且@MartinZinovsky在评论中提到的内容之后，我想知道这是不是pg gem的问题，但是另一个宝石没有被更新，特别是ActiveRecord。这是错误的一部分让我思考，因为它出现在两个错误中：
ensure its version is at the minimum required by ActiveRecord
所以，我没有像马丁建议的那样做bundle update pg，而是bundle update让它通过并更新所有可用更新的宝石。在这样做的时候，事实上它确实将所有'动作'和'主动'宝石更新为更新版本，以及'activerecord'宝石。这似乎解决了这个问题。现在rake db:migrate起作用，rails s也起作用。这是我运行bundle update之后的输出，以防其他人遇到此问题而且只有需要更新的ActiveRecord才是。也许你可以使用这个列表来查看我最后更新的内容，以找出它不适合你的原因：
运行bundle update
$ bundle update
The dependency tzinfo-data (>= 0) will be unused by any of the platforms Bundler is installing for. Bundler is installing for ruby but the dependency is only for x86-mingw32, x86-mswin32, x64-mingw32, java. To add those platforms to the bundle, run `bundle lock --add-platform x86-mingw32 x86-mswin32 x64-mingw32 java`.
Fetching gem metadata from https://rubygems.org/.............
Fetching gem metadata from https://rubygems.org/.
Resolving dependencies.....
Using rake 12.3.0
Using concurrent-ruby 1.0.5
Using i18n 0.9.5 (was 0.9.3)
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Bundle updated!