ruby-on-rails - 升级到ActiveRecord::ConnectionNotEstablished错误

Question

我试图将现有项目从Rails 3.2.3升级到Rails 4.1.4（最新版本）。我更新了我的gemfile，并且没有任何问题。我还加了

config.eager_load = false

到我的环境* .rb。当我运行服务器时，尝试访问第一页时出现以下错误……看起来好像没有数据库连接，但是我可以使用客户端来访问它。我的服务当前使用sqlite3 ..


ActiveRecord :: ConnectionNotEstablished
（ActiveRecord :: ConnectionNotEstablished）：
activerecord（4.1.4）lib / active_record / connection_adapters / abstract / connection_pool.rb：541：in
retrieve_connection'
activerecord (4.1.4) lib/active_record/connection_handling.rb:113:in retrieve_connection'
activerecord（4.1.4）lib / active_record / connection_handling.rb：87：在 connection'
activerecord (4.1.4) lib/active_record/query_cache.rb:51:in restore_query_cache_settings'中
activerecord（4.1.4）lib / active_record / query_cache.rb：43：在 rescue in call'
activerecord (4.1.4) lib/active_record/query_cache.rb:32:in调用中
activerecord（4.1.4）lib / active_record / connection_adapters / abstract / connection_pool.rb：621：in
call'
actionpack (4.1.4) lib/action_dispatch/middleware/callbacks.rb:29:in阻止通话”
activesupport（4.1.4）lib / active_support / callbacks.rb：82：在`run_callbacks'（1.5.2）中


b / rack / runtime.rb：17：in'call'
…

我的database.yml文件没有更改。它使用sqlite3

# SQLite version 3.x
#   gem install sqlite3
#
#   Ensure the SQLite 3 gem is defined in your Gemfile
#   gem 'sqlite3'
development:
  adapter: sqlite3
  database: db/development.sqlite3
  pool: 5
  timeout: 5000

# 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:
  adapter: sqlite3
  database: db/test.sqlite3
  pool: 5
  timeout: 5000

production:
  adapter: sqlite3
  database: db/production.sqlite3
  pool: 5
  timeout: 5000

Answer 1

事实证明，从3.2迁移到4.0时，有很多更改要应用于配置文件。您可以在下面的链接中查看详细信息，我能够使用postgres代替sqlite并运行该链接建议的命令来解决问题

rake rails:update

Upgrading to rails 4.0 from 3.2