Acts_as_taggable_on迁移失败

Question

我正在使用Rails 3.0.6/Ruby 1.8.7，我一直试图让acts_as_taggable_on（2.0.6）g​​em工作，但它似乎在默认迁移时失败。 日志：

== ActsAsTaggableOnMigration: migrating ====================================== 
-- create_table(:tags) 
    -> 0.3175s 
-- create_table(:taggings) 
rake aborted! 
An error has occurred, all later migrations canceled: 

Mysql2::Error: Can't create table 'project_development.taggings' (errno: 150): 
CREATE TABLE `taggings` (`id` int(11) DEFAULT NULL auto_increment PRIMARY KEY, 
`tag_id` int(11), `taggable_id` int(11), `taggable_type` varchar(255), `tagger_id` 
int(11), `tagger_type` varchar(255), `context` varchar(255), `created_at` datetime, 
FOREIGN KEY (`tag_id`) REFERENCES `tags` (`id`), FOREIGN KEY (`taggable_id`) REFERENCES 
`taggables` (`id`), FOREIGN KEY (`tagger_id`) REFERENCES `taggers` (`id`)) ENGINE=InnoDB 

所以它看起来像多态=> true属性并不像预期的那样。谷歌似乎不是很有帮助（类似的错误报告，例如http://www.ruby-forum.com/topic/194219）。任何方式来解决它？宝石的替代品？

解决 这种宝石

Answer 1

automatic_foreign_key冲突你修改迁移添加外键约束？

的行为-AS-加标签上2.0.6提供的迁移如下所示：

class ActsAsTaggableOnMigration < ActiveRecord::Migration 
     def self.up 
     create_table :tags do |t| 
      t.column :name, :string 
     end 

     create_table :taggings do |t| 
      t.column :tag_id, :integer 
      t.column :taggable_id, :integer 
      t.column :tagger_id, :integer 
      t.column :tagger_type, :string 

      # You should make sure that the column created is 
      # long enough to store the required class names. 
      t.column :taggable_type, :string 
      t.column :context, :string 

      t.column :created_at, :datetime 
     end 

     add_index :taggings, :tag_id 
     add_index :taggings, [:taggable_id, :taggable_type, :context] 
     end 

     def self.down 
     drop_table :taggings 
     drop_table :tags 
     end 
    end