Rails中的模型之間的鏈式範圍

Question

我在Rails中的模型之間查詢時遇到了一些麻煩。我有一個Message，belongs_to: booking。我的目標是將active範圍添加到Message，這取決於Booking範圍。

class Booking < ActiveRecord::Base 
    has_one :event 
    has_many :messages 

    def self.active 
    includes(:event). 
     where('events.endtime >= ? AND status IS NOT ?' 
      Time.current.beginning_of_week,    
      statuses['canceled']) 
    end 
end 

class Message < ActiveRecord::Base 
    belongs_to :booking 
    belongs_to :person 

    self.active(person_id) 
    where(person_id: person_id).merge(Booking.active) 
    end 
end 

我想找到Message小號針對特定Person在相關Booking爲active。因此，我在創建Message.active時希望使用Booking.active。

與上述實施調用Message.active(1)返回以下錯誤：

Association named 'event' was not found on Message; perhaps you misspelled it?

有什麼辦法，我可以在Message.active和實現中使用Booking.active得到Message小號回來了？

Answer 1

如果要添加在協會的條件，還需要加入他們，不僅merge或include他們，即下面應該工作：

class Booking < ActiveRecord::Base 
    # ... 
    def self.active 
    joins(:event). 
     where('events.endtime >= ? AND status IS NOT ?' 
      Time.current.beginning_of_week,    
      statuses['canceled']) 
    end 
end 

class Message < ActiveRecord::Base 
    # ... 
    self.active(person_id) 
    where(person_id: person_id).joins(:booking).merge(Booking.active) 
    end  
end 

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