无法使用 rake db:create 创建数据库

Question

sahil@sahil:~/sites/QandA$ rake db:create
/home/sahil/.rvm/gems/ruby-1.9.2-p290@global/gems/rake-0.9.2/lib/rake/version.rb:4: warning: already initialized constant MAJOR
/home/sahil/.rvm/gems/ruby-1.9.2-p290@global/gems/rake-0.9.2/lib/rake/version.rb:5: warning: already initialized constant MINOR
/home/sahil/.rvm/gems/ruby-1.9.2-p290@global/gems/rake-0.9.2/lib/rake/version.rb:6: warning: already initialized constant BUILD
/home/sahil/.rvm/gems/ruby-1.9.2-p290@global/gems/rake-0.9.2/lib/rake/version.rb:3: warning: already initialized constant NUMBERS
/home/sahil/.rvm/gems/ruby-1.9.2-p290@global/gems/rake-0.9.2/lib/rake/version.rb:9: warning: already initialized constant VERSION
/home/sahil/.rvm/gems/ruby-1.9.2-p290@global/gems/rake-0.9.2/lib/rake.rb:26: warning: already initialized constant RAKEVERSION
/home/sahil/.rvm/gems/ruby-1.9.2-p290@global/gems/rake-0.9.2/lib/rake/early_time.rb:17: warning: already initialized constant EARLY
/home/sahil/.rvm/gems/ruby-1.9.2-p290@global/gems/rake-0.9.2/lib/rake/alt_system.rb:32: warning: already initialized constant WINDOWS
/home/sahil/.rvm/gems/ruby-1.9.2-p290@global/gems/rake-0.9.2/lib/rake/application.rb:28: warning: already initialized constant DEFAULT_RAKEFILES
WARNING: Possible conflict with Rake extension: String#ext already exists
WARNING: Possible conflict with Rake extension: String#pathmap already exists
/home/sahil/.rvm/gems/ruby-1.9.2-p290@global/gems/rake-0.9.2/lib/rake/task_arguments.rb:73: warning: already initialized constant EMPTY_TASK_ARGS
/home/sahil/.rvm/gems/ruby-1.9.2-p290@global/gems/rake-0.9.2/lib/rake/invocation_chain.rb:49: warning: already initialized constant EMPTY
/home/sahil/.rvm/gems/ruby-1.9.2-p290@global/gems/rake-0.9.2/lib/rake/file_utils.rb:10: warning: already initialized constant RUBY
/home/sahil/.rvm/gems/ruby-1.9.2-p290@global/gems/rake-0.9.2/lib/rake/file_utils.rb:84: warning: already initialized constant LN_SUPPORTED
/home/sahil/.rvm/gems/ruby-1.9.2-p290@global/gems/rake-0.9.2/lib/rake/dsl_definition.rb:143: warning: already initialized constant Commands
/home/sahil/.rvm/gems/ruby-1.9.2-p290@global/gems/rake-0.9.2/lib/rake/file_list.rb:44: warning: already initialized constant ARRAY_METHODS
/home/sahil/.rvm/gems/ruby-1.9.2-p290@global/gems/rake-0.9.2/lib/rake/file_list.rb:47: warning: already initialized constant MUST_DEFINE
/home/sahil/.rvm/gems/ruby-1.9.2-p290@global/gems/rake-0.9.2/lib/rake/file_list.rb:51: warning: already initialized constant MUST_NOT_DEFINE
/home/sahil/.rvm/gems/ruby-1.9.2-p290@global/gems/rake-0.9.2/lib/rake/file_list.rb:55: warning: already initialized constant SPECIAL_RETURN
/home/sahil/.rvm/gems/ruby-1.9.2-p290@global/gems/rake-0.9.2/lib/rake/file_list.rb:61: warning: already initialized constant DELEGATING_METHODS
/home/sahil/.rvm/gems/ruby-1.9.2-p290@global/gems/rake-0.9.2/lib/rake/file_list.rb:364: warning: already initialized constant DEFAULT_IGNORE_PATTERNS
/home/sahil/.rvm/gems/ruby-1.9.2-p290@global/gems/rake-0.9.2/lib/rake/file_list.rb:370: warning: already initialized constant DEFAULT_IGNORE_PROCS
/home/sahil/.rvm/gems/ruby-1.9.2-p290@global/gems/rake-0.9.2/lib/rake.rb:64: warning: already initialized constant FileList
/home/sahil/.rvm/gems/ruby-1.9.2-p290@global/gems/rake-0.9.2/lib/rake.rb:65: warning: already initialized constant RakeFileUtils
WARNING: Global access to Rake DSL methods is deprecated.  Please include
...  Rake::DSL into classes and modules which use the Rake DSL methods.
WARNING: DSL method QandASite::Application#task called at     /home/sahil/.rvm/gems/ruby-1.9.2-p290/gems/railties-3.0.1/lib/rails/application.rb:214:in `initialize_tasks'
rake aborted!
stack level too deep

我正在使用

sahil@sahil:~/sites/QandA$ ruby -v
ruby 1.9.2p290 (2011-07-09 revision 32553) [i686-linux
sahil@sahil:~/sites/QandA$ rails -v
Rails 3.0.1
sahil@sahil:~/sites/QandA$ rvm -v
rvm 1.8.0 by Wayne E. Seguin (wayneeseguin@gmail.com) [https://rvm.beginrescueend.com/]

宝石文件

source 'http://rubygems.org'

gem 'rails', '3.0.1'

# Bundle edge Rails instead:
#     gem 'rails', :git => 'git://github.com/rails/rails.git'
gem 'rake'
gem 'mysql2','0.2.7'
gem 'heroku'
# Use unicorn as the web server
#     gem 'unicorn'

# Deploy with Capistrano
#     gem 'capistrano'

# To use debugger (ruby-debug for Ruby 1.8.7+, ruby-debug19 for Ruby 1.9.2+)
#     gem 'ruby-debug'
#     gem 'ruby-debug19', :require => 'ruby-debug'

# Bundle the extra gems:
#     gem 'bj'
#     gem 'nokogiri'
#     gem 'sqlite3-ruby', :require => 'sqlite3'
#     gem 'aws-s3', :require => 'aws/s3'

# Bundle gems for the local environment. Make sure to
# put test-only gems in this group so their generators
# and rake tasks are available in development mode:
# group :development, :test do
#       gem 'webrat'
# end

Answer 1

尝试运行

bundle exec rake db:create

有时会解决奇怪的问题。