ruby-on-rails - Acts_as_taggable_on 迁移失败

Question

我使用的是 Rails 3.0.6/Ruby 1.8.7，我一直在尝试让 acts_as_taggable_on (2.0.6) gem 正常工作，但默认迁移似乎失败了。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

所以看起来 :polymorphic => true 属性没有按预期工作。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 )。有什么办法可以解决吗？ gem 替代品？

已解决automatic_foreign_key 与这个 gem 冲突

Answer 1

您是否修改了迁移以添加外键约束？

acts-as-taggable-on 2.0.6 中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