耙中止！ Gem::LoadError: 为数据库适配器指定“postgresql”答案

【问题标题】：rake aborted! Gem::LoadError: Specified 'postgresql' for database adapter耙中止！ Gem::LoadError: 为数据库适配器指定“postgresql”
【发布时间】：2024-01-13 09:39:01
【问题描述】：

我是 Rails 新手。一切都很好，直到我更改了我的 Gemfile 以能够使用 heroku。我的 Gemfile 中有 pg，但在运行 bundle exec rake test 时仍然出现此错误@

我也不能使用 rails 控制台。

    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).
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/activerecord-4.2.0/lib/active_record/connection_adapters/connection_specification.rb:177:in `rescue in spec'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/activerecord-4.2.0/lib/active_record/connection_adapters/connection_specification.rb:174:in `spec'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/activerecord-4.2.0/lib/active_record/connection_handling.rb:50:in `establish_connection'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/activerecord-4.2.0/lib/active_record/railtie.rb:120:in `block (2 levels) in <class:Railtie>'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/activesupport-4.2.0/lib/active_support/lazy_load_hooks.rb:38:in `instance_eval'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/activesupport-4.2.0/lib/active_support/lazy_load_hooks.rb:38:in `execute_hook'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/activesupport-4.2.0/lib/active_support/lazy_load_hooks.rb:45:in `block in run_load_hooks'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/activesupport-4.2.0/lib/active_support/lazy_load_hooks.rb:44:in `each'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/activesupport-4.2.0/lib/active_support/lazy_load_hooks.rb:44:in `run_load_hooks'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/activerecord-4.2.0/lib/active_record/base.rb:316:in `<module:ActiveRecord>'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/activerecord-4.2.0/lib/active_record/base.rb:26:in `<top (required)>'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/activerecord-4.2.0/lib/active_record/migration.rb:411:in `maintain_test_schema!'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/railties-4.2.0/lib/rails/test_help.rb:19:in `<top (required)>'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/activesupport-4.2.0/lib/active_support/dependencies.rb:274:in `require'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/activesupport-4.2.0/lib/active_support/dependencies.rb:274:in `block in require'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/activesupport-4.2.0/lib/active_support/dependencies.rb:240:in `load_dependency'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/activesupport-4.2.0/lib/active_support/dependencies.rb:274:in `require'
/home/rihanna/workspace/sample_app/test/test_helper.rb:3:in `<top (required)>'
/home/rihanna/workspace/sample_app/test/controllers/static_pages_controller_test.rb:1:in `require'
/home/rihanna/workspace/sample_app/test/controllers/static_pages_controller_test.rb:1:in `<top (required)>'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/railties-4.2.0/lib/rails/test_unit/sub_test_task.rb:114:in `require'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/railties-4.2.0/lib/rails/test_unit/sub_test_task.rb:114:in `block (3 levels) in define'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/railties-4.2.0/lib/rails/test_unit/sub_test_task.rb:114:in `each'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/railties-4.2.0/lib/rails/test_unit/sub_test_task.rb:114:in `block (2 levels) in define'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/railties-4.2.0/lib/rails/test_unit/sub_test_task.rb:113:in `each'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/railties-4.2.0/lib/rails/test_unit/sub_test_task.rb:113:in `block in define'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/railties-4.2.0/lib/rails/test_unit/sub_test_task.rb:20:in `invoke_rake_task'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/railties-4.2.0/lib/rails/test_unit/testing.rake:8:in `block in <top (required)>'
Gem::LoadError: pg is not part of the bundle. Add it to Gemfile.
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/bundler-1.8.5/lib/bundler/rubygems_integration.rb:261:in `block in replace_gem'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/activerecord-4.2.0/lib/active_record/connection_adapters/postgresql_adapter.rb:16:in `<top (required)>'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/activesupport-4.2.0/lib/active_support/dependencies.rb:274:in `require'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/activesupport-4.2.0/lib/active_support/dependencies.rb:274:in `block in require'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/activesupport-4.2.0/lib/active_support/dependencies.rb:240:in `load_dependency'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/activesupport-4.2.0/lib/active_support/dependencies.rb:274:in `require'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/activerecord-4.2.0/lib/active_record/connection_adapters/connection_specification.rb:175:in `spec'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/activerecord-4.2.0/lib/active_record/connection_handling.rb:50:in `establish_connection'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/activerecord-4.2.0/lib/active_record/railtie.rb:120:in `block (2 levels) in <class:Railtie>'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/activesupport-4.2.0/lib/active_support/lazy_load_hooks.rb:38:in `instance_eval'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/activesupport-4.2.0/lib/active_support/lazy_load_hooks.rb:38:in `execute_hook'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/activesupport-4.2.0/lib/active_support/lazy_load_hooks.rb:45:in `block in run_load_hooks'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/activesupport-4.2.0/lib/active_support/lazy_load_hooks.rb:44:in `each'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/activesupport-4.2.0/lib/active_support/lazy_load_hooks.rb:44:in `run_load_hooks'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/activerecord-4.2.0/lib/active_record/base.rb:316:in `<module:ActiveRecord>'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/activerecord-4.2.0/lib/active_record/base.rb:26:in `<top (required)>'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/activerecord-4.2.0/lib/active_record/migration.rb:411:in `maintain_test_schema!'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/railties-4.2.0/lib/rails/test_help.rb:19:in `<top (required)>'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/activesupport-4.2.0/lib/active_support/dependencies.rb:274:in `require'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/activesupport-4.2.0/lib/active_support/dependencies.rb:274:in `block in require'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/activesupport-4.2.0/lib/active_support/dependencies.rb:240:in `load_dependency'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/activesupport-4.2.0/lib/active_support/dependencies.rb:274:in `require'
/home/rihanna/workspace/sample_app/test/test_helper.rb:3:in `<top (required)>'
/home/rihanna/workspace/sample_app/test/controllers/static_pages_controller_test.rb:1:in `require'
/home/rihanna/workspace/sample_app/test/controllers/static_pages_controller_test.rb:1:in `<top (required)>'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/railties-4.2.0/lib/rails/test_unit/sub_test_task.rb:114:in `require'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/railties-4.2.0/lib/rails/test_unit/sub_test_task.rb:114:in `block (3 levels) in define'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/railties-4.2.0/lib/rails/test_unit/sub_test_task.rb:114:in `each'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/railties-4.2.0/lib/rails/test_unit/sub_test_task.rb:114:in `block (2 levels) in define'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/railties-4.2.0/lib/rails/test_unit/sub_test_task.rb:113:in `each'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/railties-4.2.0/lib/rails/test_unit/sub_test_task.rb:113:in `block in define'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/railties-4.2.0/lib/rails/test_unit/sub_test_task.rb:20:in `invoke_rake_task'
/home/rihanna/.rvm/gems/ruby-2.2.0/gems/railties-4.2.0/lib/rails/test_unit/testing.rake:8:in `block in <top (required)>'
Tasks: TOP => test:run

这是我的 Gemfile：

source 'https://rubygems.org'


# Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
gem 'rails', '4.2.0'
# Use sqlite3 as the database for Active Record

#gem 'pg'
# Use SCSS for stylesheets
gem 'sass-rails', '~> 5.0'
# Use Uglifier as compressor for JavaScript assets
gem 'uglifier', '>= 1.3.0'
# Use CoffeeScript for .coffee assets and views
gem 'coffee-rails', '~> 4.1.0'
# See https://github.com/sstephenson/execjs#readme for more supported runtimes
# gem 'therubyracer', platforms: :ruby

# Use jquery as the JavaScript library
gem 'jquery-rails'
# Turbolinks makes following links in your web application faster. Read more: https://github.com/rails/turbolinks
gem 'turbolinks'
# Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
gem 'jbuilder', '~> 2.0'
# bundle exec rake doc:rails generates the API under doc/api.
gem 'sdoc', '~> 0.4.0', group: :doc

# Use ActiveModel has_secure_password
# gem 'bcrypt', '~> 3.1.7'

# Use Unicorn as the app server
# gem 'unicorn'

# Use Capistrano for deployment
# gem 'capistrano-rails', group: :development

group :development, :test do
  # Call 'byebug' anywhere in the code to stop execution and get a debugger console
  gem 'byebug'
  gem 'sqlite3'
  # Access an IRB console on exception pages or by using <%= console %> in views
  gem 'web-console', '~> 2.0'

  # Spring speeds up development by keeping your application running in the background. Read more: https://github.com/rails/spring
  gem 'spring'
end


group :production do
  gem 'pg',             '0.18.1'
  gem 'rails_12factor', '0.0.2'

end

【问题讨论】：

标签： ruby-on-rails ruby postgresql gem railstutorial.org

【解决方案1】：

请替换下面的

group :development, :test do
  # Call 'byebug' anywhere in the code to stop execution and get a debugger console
  gem 'byebug'
  gem 'sqlite3'
  # Access an IRB console on exception pages or by using <%= console %> in views
  gem 'web-console', '~> 2.0'

  # Spring speeds up development by keeping your application running in the background. Read more: https://github.com/rails/spring
  gem 'spring'
end

通过这个

group :development, :test do
  # Call 'byebug' anywhere in the code to stop execution and get a debugger console
  gem 'byebug'
  gem 'pg'
  # Access an IRB console on exception pages or by using <%= console %> in views
  gem 'web-console', '~> 2.0'

  # Spring speeds up development by keeping your application running in the background. Read more: https://github.com/rails/spring
  gem 'spring'
end

对于开发和测试，您需要 gem pg 用于 postgresql 适配器而不是 gem sqlit3

【讨论】：

运行包更新后出现此错误：您不能使用不同的版本要求两次指定相同的 gem。您指定：pg (>= 0) 和 pg (= 0.18.1) 所以我添加 gem 'pg', '0.18.1' 而不是 pg。但是现在我收到了这个错误：您的 Gemfile 不止一次列出了 gem pg (= 0.18.1)。您可能应该只保留其中一个。虽然现在这不是问题，但如果您以后只更改其中一个的版本，可能会导致错误。
这不是反过来吗？您需要 gem pg 进行生产和 gem sqlit3 进行开发。
汉娜你解决了吗？我遇到了同样的问题，我解决了只是将 pg 版本指定到 gemfile 中。在一切开始工作之前，我还必须删除 gemfile.lock 并运行包更新。顺便说一句，你不需要 pg 进行开发和测试，只在生产中使用它是完全可以的。

【解决方案2】：

类似的问题，尽管 Gemfile 是正确的（生产中的 pg 和 dev 中的 sqlite，database.yml 有 postgresql）。 bundle 拒绝拾取 pg gem。

我正在编写 heroku 实例的创建脚本，所以所有这些都在 cli 上

我的解决方案

显式添加 postgress 附加组件 (heroku addons:create heroku-postgresql:hobby-dev --app <myappname>)。这似乎迫使它足够早地创建 DATABASE_URL (Created postgresql-xxxxxxx-9999 as DATABASE_URL)。此时 bundle 似乎起作用了。
我考虑过/尝试过并为每个环境创建保留的其他东西是确保您在流程中强制尽快设置变量heroku config:set --app <mayappname> RAILS_ENV=production

【讨论】：