HABTM链接表在安装引擎中未采用isolate_namespace值

Question

我目前正在开发可安装引擎。在发动机我有以下两种模式：

module Ems 
    class Channel < ActiveRecord::Base 
     has_and_belongs_to_many :categories 
    end 
    end 

    module Ems 
    class Category < ActiveRecord::Base 
     has_and_belongs_to_many :channels 
    end 
    end 

这些数据库迁移文件：

class CreateEmsChannels < ActiveRecord::Migration 
    def change 
     create_table :ems_channels do |t| 
     t.string :slug 
     t.string :name 

     t.timestamps 
     end 
    end 
    end 

    class CreateEmsCategories < ActiveRecord::Migration 
    def change 
     create_table :ems_categories do |t| 
     t.string :slug 
     t.string :name 
     t.text :strapline 

     t.timestamps 
     end 
    end 
    end 


    class CreateEmsCategoriesChannels < ActiveRecord::Migration 
    def up 
     # Create the association table 
     create_table :ems_categories_channels, :id => false do |t| 
     t.integer :category_id, :null => false 
     t.integer :channel_id, :null => false 
     end 

     # Add table index 
     add_index :ems_categories_channels, [:category_id, :channel_id], :unique => true 
    end 
    end 

的问题，当我尝试检索相关的对象开始。 作为一个例子，当我打电话@channel.get :categories我收到以下错误：

Mysql2::Error: Table 'ems_development.categories_channels' doesn't exist: 
SELECT `ems_categories`.* 
FROM `ems_categories` 
INNER JOIN `categories_channels` 
ON `ems_categories`.`id` = `categories_channels`.`category_id` 
WHERE `categories_channels`.`channel_id` = 1 

正如你可以看到它的缺失关闭链接表isolate_namespace价值，因为它应该寻找在桌子上ems_categories_channels不categories_channels协会

任何人都有类似的问题，或者我错过了什么？

Answer 1

您可以明确设置连接表名称（per the documentation）。

module Ems 
    class Channel < ActiveRecord::Base 
     has_and_belongs_to_many :categories, :join_table => 'ems_categories_channels' 
    end 
    end 

    module Ems 
    class Category < ActiveRecord::Base 
     has_and_belongs_to_many :channels, :join_table => 'ems_categories_channels' 
    end 
    end