ror表的几个级联方法

order.rb:

 class Order < ActiveRecord::Base
	has_many :items
 end

类方法 实例方法 属性

    * find(*args)
    * find_by_sql(sql)
    * exists?(id)
    * create(attributes)
    * update(id, attributes)
    * update_all(updates, conditions
    * delete(id)
    * delete_all(conditions)
    * ...



    * add_items
    * build_to_items
    * create_in_items
    * find_all_in_items
    * find_in_items
    * has_items?
    * items
    * items=
    * items_count
    * remove_items



    * id
    * name