如何在rails中优化多态新闻源？

Question

这是我的模型:

class User < ActiveRecord::Base
  has_many :activities
  has_many :requests

class Activity < ActiveRecord::Base
  belongs_to :user
  belongs_to :object, :polymorphic => true

我希望获得所有用户活动并显示它们

Activity.where(:user_id => current_user.id).include(:object)

问题是我不能急于加载对象模型,因为它是多态的我如何克服这个问题？

Answer 1

多态关联支持急切加载.您需要执行以下操作:

Activity.find(:all, :include => :objectable, :conditions => {:user_id => current_user.id})

虽然您需要确保已在关联模型上正确定义了多态关系.

如需进一步帮助,请参阅:http: //api.rubyonrails.org/classes/ActiveRecord/Associations/ClassMethods.html#label-Eager+loading+of+associations

多态部分位于"Eager loading of Associations"部分的末尾.