activerecord查询数组数组

Question

我有以下型号：

Notification
  belongs_to :receiver, class_name: 'User'
  # has a sent_email boolean column default set to false

User
  has_many :received_notifications, class_name: 'Notification', foreign_key: 'receiver_id', inverse_of: :receiver
  has_one :alert

Alert
  belongs_to :user
  # has a frequency integer column

对于将警报频率设置为1的所有用户，我想抓取sent_email为false的所有通知，并且我希望返回结果如下：

    [
       {user object => [<all of the notifications for user 1>]},
       {user object => [<all of the notifications for user 2>]}    
    ]

我希望它最多是1个或2个查询。

activerecord查询会是什么样的？

Answer 1

您可以使用includes。

u = User.includes(:received_notifications, :alert)
        .where("alerts.frequency_discussion_alerts = ? AND notifications.sent_email = ?", 1, false)
        .references(:notifications,:alerts)

现在批量处理，您可以获取用户并完成工作。

 u.find_each { |u| u.received_notifications }