在 Rails Migration 中触发删除查询的更好方法是什么

Question

我对 Rails 有点陌生，我想写一些 self.down 查询。目前我正在对整个查询进行硬编码。有更简单的方法吗？

  def self.down
    delete("delete from trigger_events where name = 'CHANGE_APPROVED'")
    delete("delete from notifications where trigger_event_id = 5")
    delete("delete from notification_recipients where notification_id = 5")
    delete("delete from n_m_d where notification_id = 5 and msg_index=15")
  end

谢谢

Answer 1

你可以用 ActiveRecord 风格来做到这一点：

  def self.down
    TriggerEvents.find_by_name('CHANGE_APPROVED').destroy_all
    Notifications.find_by_trigger_event_id(5).destroy_all
    NotificationRecipients.find_by_notification_id(5).destroy_all
    NMD.find_by_notification_id_and_msg_index(5,15).destroy_all
  end

Answer 2

根据@shingara，但进行了修改以处理未找到的情况

def self.down
  TriggerEvents.find_all_by_name('CHANGE_APPROVED').map(&:destroy)
  Notifications.find_all_by_trigger_event_id(5).map(&:destroy)
  NotificationRecipients.find_all_by_notification_id(5).map(&:destroy)
  NMD.find_all_by_notification_id_and_msg_index(5,15).map(&:destroy)
end