rake db:migrate 对我不起作用

Question

我收到此错误

 rake db:migrate (in
   /Users/john/Sites/my_app) rake aborted!
   Don't know how to build task
   'db:migrate'

当我跟踪错误时，我得到

rake aborted! Don't know how to build task 'db:migrate' 
/usr/local/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:1728:in `[]' 
/usr/local/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2050:in `invoke_task' 
/usr/local/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in `top_level' 
/usr/local/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in `each' 
/usr/local/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in `top_level'
/usr/local/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2068:in `standard_exception_handling' 
/usr/local/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2023:in `top_level' 
/usr/local/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2001:in `run' 
/usr/local/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2068:in `standard_exception_handling' 
/usr/local/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:1998:in `run' 
/usr/local/lib/ruby/gems/1.8/gems/rake-0.8.7/bin/rake:31 
/usr/local/bin/rake:19:in `load' /usr/local/bin/rake:19

My Rakefile is

require(File.join(File.dirname(__FILE__), 'config', 'boot'))

require 'rake'
require 'rake/testtask'
require 'rake/rdoctask'

Answer 1

对于 Ruby on Rails 2.3，您的 Rakefile 末尾应该有以下附加行：

require 'tasks/rails'