Ruby on rails 尽管I'；我没有在我的gem文件中使用PG gem，并且database.yml不'；不包括任何Postgresql引用

我从我的机器上删除了postgres

brew rm postgresql --force
rm -rf /usr/local/var/postgres

我创建了一个新的rails应用程序。这是我的标准文件

source 'https://rubygems.org'
gem 'rails', '~> 5.0.0', '>= 5.0.0.1'
gem 'sqlite3'
gem 'puma', '~> 3.0'
gem 'sass-rails', '~> 5.0'
gem 'uglifier', '>= 1.3.0'
gem 'coffee-rails', '~> 4.2'
gem 'jquery-rails'
gem 'turbolinks', '~> 5'
gem 'jbuilder', '~> 2.5'

group :development, :test do
  gem 'byebug', platform: :mri
end

group :development do
  gem 'web-console'
  gem 'listen', '~> 3.0.5'
  gem 'spring'
  gem 'spring-watcher-listen', '~> 2.0.0'
end

gem 'tzinfo-data', platforms: [:mingw, :mswin, :x64_mingw, :jruby]

然后

虽然我没有在我的gem文件中指定任何pg gem，但在尝试访问localhost时出现了错误

> 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).
> Extracted source (around line #176):

require path_to_adapter
rescue Gem::LoadError => eraise Gem::LoadError, 
"Specified '#{spec[:adapter]}' for database adapter, 
but the gem is not loaded. 
Add `gem '#{e.name}'` to your Gemfile   
(and ensure its version is at the minimum required by ActiveRecord)."
rescue LoadError => eraise LoadError,  
"Could not load '#{path_to_adapter}'. 
Make sure that the adapter in config/database.yml is valid. 
If you use an adapter other than 'mysql2', 'postgresql' or 'sqlite3'     
add the necessary adapter gem to the Gemfile.", e.backtrace
end

这是我的database.yml文件，它也不包含任何postgres

# SQLite version 3.x
#   gem install sqlite3
#
#   Ensure the SQLite 3 gem is defined in your Gemfile
#   gem 'sqlite3'
#
default: &default
  adapter: sqlite3
  pool: 5
  timeout: 5000

development:
  <<: *default
  database: db/development.sqlite3

# Warning: The database defined as "test" will be erased and
# re-generated from your development database when you run "rake".
# Do not set this db to the same as development or production.
test:
  <<: *default
  database: db/test.sqlite3

production:
  <<: *default
  database: db/production.sqlite3

#SQLite版本3.x
#gem安装sqlite3
#
#确保在gem文件中定义了SQLite 3 gem
#gem'sqlite3'
#
默认值：&默认值
适配器：sqlite3
游泳池：5
超时：5000
发展：
在database.yml文件中，您仍然将postgres列为适配器。一旦您更改了database.yml以反映您没有使用postgres这一事实，您将需要运行
rake db:drop db:create db:migrate
我也有同样的问题

在控制台中写入：

echo$DATABASE\u URL
如果结果是：

Postgresql://user:password@本地主机/数据库
在您的.bash_配置文件或.profile中查找

导出数据库\u URL=“postgresql://user:password@本地主机/数据库“

评论这句话，让我感到高兴

读这里


第3.5节

“当提供重复的连接信息时，环境变量（DATABASE_URL）将优先”
my DATABASE.yml不包括任何postgres引用。重新编辑了我的问题并包含了yml内容我运行了rake db:drop db:create db:migrate

，并得到了错误rake中止！Gem:：LoadError:为数据库适配器指定了“postgresql”，但未加载Gem。将

gem'pg'

添加到您的gem文件中（并确保其版本为ActiveRecord要求的最低版本）。

# SQLite version 3.x
#   gem install sqlite3
#
#   Ensure the SQLite 3 gem is defined in your Gemfile
#   gem 'sqlite3'
#
default: &default
  adapter: sqlite3
  pool: 5
  timeout: 5000

development:
  <<: *default
  database: db/development.sqlite3

# Warning: The database defined as "test" will be erased and
# re-generated from your development database when you run "rake".
# Do not set this db to the same as development or production.
test:
  <<: *default
  database: db/test.sqlite3

production:
  <<: *default
  database: db/production.sqlite3