Heroku with rails 5错误Gem :: LoadError：为数据库适配器指定’postgresql’
我是Rails的初学者，在部署到Heroku时我看到了一些问题。
之前我使用的是SQLite3，后来当我明白我需要postgresql时，我安装了相同的并在本地机器上工作。
从sqlite迁移到postgresql后，一次部署正常。 现在我看到一些问题。
Heroku日志，Gem文件和Database.yml详细信息如下。
请有人帮助我。
提前谢谢…… !!!
Gem文件的一部分：
group :development, :test do gem 'pg', '~> 1.0.0' gem 'rails_12factor' #gem 'sqlite3' # Call 'byebug' anywhere in the code to stop execution and get a debugger console gem 'byebug', platforms: [:mri, :mingw, :x64_mingw] # Adds support for Capybara system testing and selenium driver gem 'capybara', '~> 2.13' gem 'selenium-webdriver' end group :production do gem 'pg', '~> 1.0.0' gem 'rails_12factor' end group :development do # Access an IRB console on exception pages or by using anywhere in the code. gem 'web-console', '>= 3.3.0' end # Windows does not include zoneinfo files, so bundle the tzinfo-data gem gem 'tzinfo-data', platforms: [:mingw, :mswin, :x64_mingw, :jruby] database.yml的：
development: adapter: postgresql encoding: unicode database: database_postgresql pool: 5 username: postgres password: secret test: adapter: postgresql encoding: unicode database: database_postgresql_test pool: 5 username: postgres password: secret production: adapter: postgresql encoding: unicode database: database_postgresql pool: 5 username: postgres password: secret
Heroku日志的一部分。
remote: -----> Installing node-v6.11.1-linux-x64 remote: -----> Detecting rake tasks remote: -----> Preparing app for Rails asset pipeline remote: Running: rake assets:precompile remote: Yarn executable was not detected in the system. remote: Download Yarn at https://yarnpkg.com/en/docs/install remote: I, [2018-01-15T13:38:08.180450 #590] INFO -- : Writing /tmp/build_3dd0bceef080f0d8f6be5bc51b9d4a48/public/assets/jumbotron--032aba6cd1415006731040523573e7138c703aedc6d1f46b3622cbe4c9feec27.jpg remote: rake aborted! remote: 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). remote: /tmp/build_3dd0bceef080f0d8f6be5bc51b9d4a48/vendor/bundle/ruby/2.3.0/gems/activerecord-5.1.4/lib/active_record/connection_adapters/connection_specification.rb:188:in `rescue in spec' remote: /tmp/build_3dd0bceef080f0d8f6be5bc51b9d4a48/vendor/bundle/ruby/2.3.0/gems/sprockets-rails-3.2.1/lib/sprockets/rails/task.rb:67:in `block (2 levels) in define' remote: /tmp/build_3dd0bceef080f0d8f6be5bc51b9d4a48/vendor/bundle/ruby/2.3.0/gems/rake-12.3.0/exe/rake:27:in `' remote: Tasks: TOP => assets:precompile remote: (See full trace by running task with --trace) remote: ! remote: ! Precompiling assets failed. remote: ! remote: ! Push rejected, failed to compile Ruby app. remote: remote: ! Push failed remote: Verifying deploy... remote: remote: ! Push rejected to damp-beyond-28813.
如果您最近将您的应用程序部署到Heroku，并且在您尝试使用Heroku应用程序链接时遇到“应用程序崩溃”错误，但其他所有内容似乎都已按顺序排列，则很可能是由于新版本的'pg' gem 。 Postgres发布了一个新版本的gem，它似乎还不完全兼容，所以在你的group production下的Gemfile中改变了这一行：
gem 'pg' OR gem 'pg', '~> 1.0.0'
至
gem 'pg', '~> 0.11' OR gem 'pg', '~> 0.20.0'
注意：在>之前的波形符号，这不是破折号
在Gemfile的组生产中进行此更新后，请确保运行bundle install --without production （更新Gemfile.lock文件），执行git add / commit循环，然后重新部署到Heroku。
为了良好实践
在没有:group情况下使用pg gem一次，因为您的数据库对于development和production!都是相同的production!