运行 Rails 时无法加载“active_record/connection_adapter/sqlite3_adapter”答案

【问题标题】：Could not load 'active_record/connection_adapters/sqlite3_adapter' when running Rails运行 Rails 时无法加载“active_record/connection_adapter/sqlite3_adapter”
【发布时间】：2020-07-04 15:20:08
【问题描述】：

    source 'https://rubygems.org'


# Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
gem 'rails', '4.2.11'
# Use sqlite3 as the database for Active Record
gem 'sqlite3', '1.3.13' , platform: :ruby
group :development, :production do
  gem 'pg'
end

group :test do
  gem 'sqlite3', '1.3.13'
end
# 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/rails/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'
end

group :development do
  # Access an IRB console on exception pages or by using <%= console %> in views
  gem 'web-console', '~> 2.0'
end

# Windows does not include zoneinfo files, so bundle the tzinfo-data gem
gem 'tzinfo-data', platforms: [:mingw, :mswin, :x64_mingw, :jruby]

无法加载“active_record/connection_adapter/sqlite3_adapter”。确保 config/database.yml 中的适配器有效。如果你使用除了“mysql”、“mysql2”、“postgresql”或“sqlite3”之外的适配器添加 Gemfile 的必要适配器 gem。

块引用

C:/Ruby26-x64/lib/ruby/gems/2.6.0/gems/activesupport-4.2.11/lib/active_support/c ore_ext/object/duplicable.rb:111: warning: BigDecimal.new is deprecated; use Big Decimal() method instead.
=> Booting WEBrick
=> Rails 4.2.11 application starting in development on http://localhost:3000
=> Run `rails server -h` for more startup options
=> Ctrl-C to shutdown server [2020-03-23 23:42:51] INFO  WEBrick 1.4.2 [2020-03-23 23:42:51] INFO  ruby 2.6.5 (2019-10-01) [x64-mingw32] [2020-03-23 23:42:51] INFO  WEBrick::HTTPServer#start: pid=3492 port=3000

【问题讨论】：

config/database.yml 说你的适配器是什么？你bundle install了吗？你运行的是常规的 Ruby 还是 JRuby？
default: &default adapter: sqlite3 pool: 5 timeout: 5000 development:
检查sqlite3 在执行bundle show 时是否出现。不过，您真的打算在这里使用 Postgres 吗？
常规红宝石....
不需要发布所有内容，只需询问sqlite3。看起来它在加载该依赖项时遇到问题，因此可能需要卸载并重新安装该 gem。

标签： ruby-on-rails ruby

【解决方案1】：

这是platform 在Gemfile 上使用的文档：https://bundler.io/v2.0/man/gemfile.5.html#PLATFORMS

上面写着：

红宝石

C Ruby (MRI)、Rubinius 或 TruffleRuby，但不是 Windows

您的 sqlite3 依赖项适用于 ruby 平台，因此在 Windows 上不会安装它。

你似乎在 Windows 上。因此不会安装sqlite3。

【讨论】：