ruby-on-rails - Rails 在使用 PostgreSQL 时出错

Question

我正在尝试为我的 Rails 应用程序使用 PostgreSQL 而不是 SQLite3，因为 Heroku 需要 PostgreSQL，我想在其中部署该应用程序。使用 Postgres 标志(即 --databse=postgresql)启动我的应用程序工作正常。但是，在将 gem twitter-boostrap-rails 添加到我的 Gemfile 并运行 bundle install 后，我收到有关 SQLite3 的错误:

active_record/connection_adapters/connection_specification.rb:190:in

rescue in spec': Specified 'sqlite3' for database adapter, but the
gem is not loaded. Addgem 'sqlite3'` to your Gemfile (and ensure its version is at the minimum required by ActiveRecord)

这是我的Gemfile:

source 'https://rubygems.org'

gem "therubyracer"
gem "less-rails"
gem "twitter-bootstrap-rails"


# Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
gem 'rails', '4.1.4'
# Use postgresql as the database for Active Record
gem 'pg'
# 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.              
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

# Spring speeds up development by keeping your application running in the background.   
gem 'spring',        group: :development

# 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]

gem 'rails_12factor', group: :production>

这是我的database.yml:

----------


# PostgreSQL. Versions 8.2 and up are supported.
#
# Install the pg driver:
#   gem install pg
# On OS X with Homebrew:
#   gem install pg -- --with-pg-config=/usr/local/bin/pg_config
# On OS X with MacPorts:
#   gem install pg -- --with-pg-config=/opt/local/lib/postgresql84/bin/pg_config
# On Windows:
#   gem install pg
#       Choose the win32 build.
#       Install PostgreSQL and put its /bin directory on your path.
#
# Configure Using Gemfile
# gem 'pg'
#
default: &default
  adapter: postgresql
  encoding: unicode
  # For details on connection pooling, see rails configuration guide
  # http://guides.rubyonrails.org/configuring.html#database-pooling
  pool: 5

development:
  <<: *default

为什么会出现此错误，我该如何解决该问题？

Answer 1

尝试为开发显式设置数据库配置。看起来 database.yml 没有正确对齐。

development:
  adapter: postgresql
  encoding: utf8
  database: your_db
  host: 127.0.0.1
  pool: 5
  username: your_db_username
  password: your_db_password