新しい空の Rails (4.0) サイトを実行すると、次のエラーが表示されます。
Specified 'sqlite3' for database adapter, but the gem is not loaded. Add `gem 'sqlite3'` to your Gemfile.
devkit で構築された有効な sqlite3 gem があります。私はそのためにばかげたテストをしました:
w:...> ruby hello.rb
hello world
test.db is done.
以下に示すように、「test.db」と呼ばれる空のデータベースも作成されます。簡単な Ruby スクリプト:
require "sqlite3"
puts "hello world"
# Open a database
db = SQLite3::Database.new "test.db"
puts "test.db is done."
私の結論は、sqlite3 gem は正常に動作しており、レールのどこかに問題があるということです。提案や説明を歓迎します。
Gemfileに関するコメントに続くちょっとした更新:
# Use sqlite3 as the database for Active Record
gem 'sqlite3', group: [:development, :test]
さらに、bundle showコマンドを使用しましたが、これは奇妙です:
w:...> bundle show sqlite3
Could not find gem 'sqlite3'.
Did you mean sqlite3?
バンドル インストールを実行すると、出力リストに sqlite3が含まれません。Gemfile を追加する必要があり、それ以外はすべて「rails new train」コマンド (プロジェクト名はもちろん' train ') によって箱から出してすぐに生成されました。
環境は、Windows 7 64 ビット PC に Ruby v2、Rails v4 をインストールしたものです。Ruby のさまざまなバージョンを管理するための PIK があります。提案を歓迎します。事前に感謝します、ウィル。
すべてが箱から出してすぐに使用できる Rails 4/Ruby 2 構成です。理論的には新規インストールが機能するはずなので、サーバーのスタックダンプも追加しています。
Gem::LoadError (Specified 'sqlite3' for database adapter, but the gem is not loaded. Add `gem 'sqlite3'` to your Gemfile.):
activerecord (4.0.0) lib/active_record/connection_adapters/connection_specification.rb:58:in `rescue in resolve_hash_connection'
activerecord (4.0.0) lib/active_record/connection_adapters/connection_specification.rb:55:in `resolve_hash_connection'
activerecord (4.0.0) lib/active_record/connection_adapters/connection_specification.rb:46:in `resolve_string_connection'
activerecord (4.0.0) lib/active_record/connection_adapters/connection_specification.rb:30:in `spec'
activerecord (4.0.0) lib/active_record/connection_handling.rb:39:in `establish_connection'
activerecord (4.0.0) lib/active_record/railtie.rb:175:in `block (2 levels) in <class:Railtie>'
activesupport (4.0.0) lib/active_support/lazy_load_hooks.rb:38:in `instance_eval'
activesupport (4.0.0) lib/active_support/lazy_load_hooks.rb:38:in `execute_hook'
activesupport (4.0.0) lib/active_support/lazy_load_hooks.rb:45:in `block in run_load_hooks'
activesupport (4.0.0) lib/active_support/lazy_load_hooks.rb:44:in `each'
activesupport (4.0.0) lib/active_support/lazy_load_hooks.rb:44:in `run_load_hooks'
activerecord (4.0.0) lib/active_record/base.rb:322:in `<module:ActiveRecord>'
activerecord (4.0.0) lib/active_record/base.rb:22:in `<top (required)>'
activerecord (4.0.0) lib/active_record/query_cache.rb:50:in `restore_query_cache_settings'
activerecord (4.0.0) lib/active_record/query_cache.rb:43:in `rescue in call'
activerecord (4.0.0) lib/active_record/query_cache.rb:32:in `call'
activerecord (4.0.0) lib/active_record/connection_adapters/abstract/connection_pool.rb:626:in `call'
activerecord (4.0.0) lib/active_record/migration.rb:369:in `call'
actionpack (4.0.0) lib/action_dispatch/middleware/callbacks.rb:29:in `block in call'
activesupport (4.0.0) lib/active_support/callbacks.rb:373:in `_run__398267657__call__callbacks'
activesupport (4.0.0) lib/active_support/callbacks.rb:80:in `run_callbacks'
actionpack (4.0.0) lib/action_dispatch/middleware/callbacks.rb:27:in `call'
actionpack (4.0.0) lib/action_dispatch/middleware/reloader.rb:64:in `call'
actionpack (4.0.0) lib/action_dispatch/middleware/remote_ip.rb:76:in `call'
actionpack (4.0.0) lib/action_dispatch/middleware/debug_exceptions.rb:17:in `call'
actionpack (4.0.0) lib/action_dispatch/middleware/show_exceptions.rb:30:in `call'
railties (4.0.0) lib/rails/rack/logger.rb:38:in `call_app'
railties (4.0.0) lib/rails/rack/logger.rb:21:in `block in call'
activesupport (4.0.0) lib/active_support/tagged_logging.rb:67:in `block in tagged'
activesupport (4.0.0) lib/active_support/tagged_logging.rb:25:in `tagged'
activesupport (4.0.0) lib/active_support/tagged_logging.rb:67:in `tagged'
railties (4.0.0) lib/rails/rack/logger.rb:21:in `call'
actionpack (4.0.0) lib/action_dispatch/middleware/request_id.rb:21:in `call'
rack (1.5.2) lib/rack/methodoverride.rb:21:in `call'
rack (1.5.2) lib/rack/runtime.rb:17:in `call'
activesupport (4.0.0) lib/active_support/cache/strategy/local_cache.rb:83:in `call'
rack (1.5.2) lib/rack/lock.rb:17:in `call'
actionpack (4.0.0) lib/action_dispatch/middleware/static.rb:64:in `call'
railties (4.0.0) lib/rails/engine.rb:511:in `call'
railties (4.0.0) lib/rails/application.rb:97:in `call'
rack (1.5.2) lib/rack/lock.rb:17:in `call'
rack (1.5.2) lib/rack/content_length.rb:14:in `call'
rack (1.5.2) lib/rack/handler/webrick.rb:60:in `service'
B:/lang/ruby/v02.00/lib/ruby/2.0.0/webrick/httpserver.rb:138:in `service'
B:/lang/ruby/v02.00/lib/ruby/2.0.0/webrick/httpserver.rb:94:in `run'
B:/lang/ruby/v02.00/lib/ruby/2.0.0/webrick/server.rb:295:in `block in start_thread'