ruby-on-rails - 使用rake db:create命令时出错(Ruby on Rails)

Question

我刚开始在Rails上使用ruby，并创建了一个新的rails项目文件夹。
现在，我尝试使用rake db：create命令，但出现以下错误。
请帮忙。

NOTE: Gem.source_index is deprecated, use Specification. It will be removed on or after 2011-11-01.
Gem.source_index called from /home/samsung/ruby/blog/config/../vendor/rails/railties/lib/rails/gem_dependency.rb:21.
NOTE: Gem::SourceIndex#initialize is deprecated with no replacement. It will be removed on or after 2011-11-01.
Gem::SourceIndex#initialize called from /home/samsung/ruby/blog/config/../vendor/rails/railties/lib/rails/vendor_gem_source_index.rb:100.
NOTE: Gem::SourceIndex#add_spec is deprecated, use Specification.add_spec. It will be removed on or after 2011-11-01.
Gem::SourceIndex#add_spec called from /usr/lib/ruby/vendor_ruby/1.8/rubygems/source_index.rb:91.
NOTE: Gem::SourceIndex#add_spec is deprecated, use Specification.add_spec. It will be removed on or after 2011-11-01.
Gem::SourceIndex#add_spec called from /usr/lib/ruby/vendor_ruby/1.8/rubygems/source_index.rb:91.
NOTE: Gem::SourceIndex#add_spec is deprecated, use Specification.add_spec. It will be removed on or after 2011-11-01.
Gem::SourceIndex#add_spec called from /usr/lib/ruby/vendor_ruby/1.8/rubygems/source_index.rb:91.
NOTE: Gem::SourceIndex#add_spec is deprecated, use Specification.add_spec. It will be removed on or after 2011-11-01.
Gem::SourceIndex#add_spec called from /usr/lib/ruby/vendor_ruby/1.8/rubygems/source_index.rb:91.
NOTE: Gem::SourceIndex#add_spec is deprecated, use Specification.add_spec. It will be removed on or after 2011-11-01.
Gem::SourceIndex#add_spec called from /usr/lib/ruby/vendor_ruby/1.8/rubygems/source_index.rb:91.
NOTE: Gem::SourceIndex#add_spec is deprecated, use Specification.add_spec. It will be removed on or after 2011-11-01.
Gem::SourceIndex#add_spec called from /usr/lib/ruby/vendor_ruby/1.8/rubygems/source_index.rb:91.
WARNING: 'require 'rake/rdoctask'' is deprecated.  Please use 'require 'rdoc/task' (in RDoc 2.4.2+)' instead.
    at /usr/lib/ruby/vendor_ruby/rake/rdoctask.rb
Please install RDoc 2.4.2+ to generate documentation.
rake aborted!
no such file to load -- sqlite3

Tasks: TOP => db:create
(See full trace by running task with --trace)

Answer 1

您需要确保将要使用的gem添加到gemfile中：

gem 'sqlite3'

然后，要从应用程序根目录中的命令行安装gem：

bundle install

这将导致它们是自动需要的，从而修复了以下错误：

no such file to load -- sqlite3