无法启动 rails 服务器 - sqlite3 适配器错误

Question

我正在努力自学rails上的ruby，并试图创建一个简单的应用程序。我在上学习教程http://guides.rubyonrails.org/getting_started.html#creating-一个新的电子邮件项目，但启动服务器时遇到困难。当我尝试启动服务器并转到localhost时，

Could not load 'active_record/connection_adapters/sqlite3_adapter'. Make sure that the adapter in
config/database.yml is valid. If you use an adapter other than 'mysql', 'mysql2', 'postgresql' or
'sqlite3' add the necessary adapter gem to the Gemfile.

我试图在其他问题上找到解决方案/原因，但没有成功。

我的Gemfile看起来像这个

source 'https://rubygems.org'
# Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
gem 'rails', '4.1.6'
# Use sqlite3 as the database for Active Record
gem 'sqlite3'
# Use SCSS for stylesheets
gem 'sass-rails', '~> 4.0.3'
# Use Uglifier as compressor for JavaScript assets
gem 'uglifier', '>= 1.3.0'
# Use CoffeeScript for .js.coffee assets and views
gem 'coffee-rails', '~> 4.0.0'
# 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
# Use debugger
# gem 'debugger', group: [:development, :test]
# Windows does not include zoneinfo files, so bundle the tzinfo-data gem
gem 'tzinfo-data', platforms: [:mingw, :mswin]

我正在使用Ruby 2.1.3

当我输入时

宝石列表

我发现我在跑步轨道4.1.6sqlite3（1.3.9 x86-ming32）

有人能给我指正确的方向吗？

Answer 1

确保您的config/database.yml为当前环境设置了适当的数据库驱动程序：

development:
  adapter: sqlite3 # check if you have sqlite3 here
  encoding: ...
  database: ...
  pool: ...
  username: ...
  password: ...

另外，不要忘记为您希望在.

Answer 2

我从未使用过sqlite，但从错误中我猜database.yml中有一行写着：

adapter: sqlite3_adapter

应该是：

adapter: sqlite3

编辑：忍者

Answer 3

您可以将sqlite3gem放入Gemfile 中进行开发

组：开发do
gem"sqlite3"
//*你的另一颗宝石只有发展
结束

Answer 4

database.yml文件中的适配器错误。使用这个：

adapter: sqlite3