Question

运行Sinatra 1.0，我想在我的程序中添加一个数据库表。在我的Rakefile中，我有一个任务

task :environment do   
    ActiveRecord::Base.establish_connection(YAML::load(File.open('config/database.yml'))["development"])      
end

我的命名空间中有一个调用迁移代码的迁移任务：

    namespace :related_products do  
      desc "run any migrations we may have in db/migrate"
      task :migrate => :environment do   
        ActiveRecord::Migrator.migrate('db/migrate', ENV["VERSION"] ? ENV["VERSION"].to_i : nil )   
    end

我的控制台在调用ActiveRecord :: MIgrator.migrate（）时发出错误。耙子流产了！未定义的方法`info'代表nil：NilClass

迁移代码本身非常简单......并且没有提供关于这个缺少的信息类是什么的线索。

    class CreateStores < ActiveRecord::Migration
      def self.up       
        create_table :stores do |t|
          t.string :name
          t.string :access_url
          t.timestamps
        end
      end

      def self.down
        drop_table :stores
      end
    end

我在这里有点神秘，正在寻找一些可能出错的线索。谢谢！

简单的回溯显示攻击线只是对迁移的调用：

    rake aborted!
undefined method `info' for nil:NilClass
/Library/Ruby/Gems/1.8/gems/activerecord-2.3.5/lib/active_record/migration.rb:473:in `migrate'
/Library/Ruby/Gems/1.8/gems/activerecord-2.3.5/lib/active_record/migration.rb:472:in `each'
/Library/Ruby/Gems/1.8/gems/activerecord-2.3.5/lib/active_record/migration.rb:472:in `migrate'
/Library/Ruby/Gems/1.8/gems/activerecord-2.3.5/lib/active_record/migration.rb:400:in `up'
/Library/Ruby/Gems/1.8/gems/activerecord-2.3.5/lib/active_record/migration.rb:383:in `migrate'
/Users/baz/Documents/workspace/rp/Rakefile:26
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:636:in `call'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:636:in `execute'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:631:in `each'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:631:in `execute'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:597:in `invoke_with_call_chain'
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/monitor.rb:242:in `synchronize'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:590:in `invoke_with_call_chain'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:583:in `invoke'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2051:in `invoke_task'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in `top_level'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in `each'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in `top_level'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2068:in `standard_exception_handling'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2023:in `top_level'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2001:in `run'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2068:in `standard_exception_handling'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:1998:in `run'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/bin/rake:31
/usr/bin/rake:19:in `load'
/usr/bin/rake:19

Answer 1

我刚遇到同样的问题，修复方法是给ActiveRecord一些关于输出日志信息的信息。

我将以下内容添加到我的Rakefile

中

ActiveRecord::Base.logger = Logger.new(STDOUT)
ActiveRecord::Migration.verbose = true

-Timmy

尝试将ActiveRecord与Sinatra一起使用，迁移失败了问题

1 个答案: