Rails 3 ActiveRecord 预先加载范围 [英] Rails 3 ActiveRecord eager loading of scope

问题描述

请帮帮我.我有一些与其他模型有很多关联的模型.例如:个人资料 => has_many :statistics在统计模型内部，我有一些范围:

Help me please. I have some model which has_many association with other model. For example: profile => has_many :statistics And inside of statistic model I have some scope:

scope last_ten, limit(10).order('online desc')

问题是我如何为这个范围使用预先加载?我不需要每个配置文件的统计数据记录.仅限范围.

And question is how can I use eager load for this scope? I don't need every record of statistics for profile. Only scoped.

现在我只能使用

 User.profiles.includes(:statistics)

谢谢.

推荐答案

如此处所述:http://api.rubyonrails.org/classes/ActiveRecord/Associations/ClassMethods.html

最好定义一个自定义关系:

It's better to define a custom relation:

class Profile < ActiveRecord::Base
  has_many :most_recent_stats, :class_name => 'Statistic', :order => 'online DESC', :limit => 10
  ...
end

User.profiles.includes(:most_recent_stats)

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