Django經理或更好的計劃

Question

我只是得到Django Managers我的手，我發現自己正在做這種類型的編程。我期待看看是否有辦法消除明顯的重複..我相信我需要定義使用get_query_set來指代我自己？

對我的問題要非常清楚。我重複地不得不通過細分以找出要過濾的行。我認爲有一種更簡單的方法，我只是不確定它是什麼。

感謝您的期待！

--- models.py

class Subdivision(models.Model): 
    objects = SubdivisionManager() 

--- managers.py

class SubdivisionManager(models.Manager): 
    """A generic manager with metros""" 


    def is_metro_sample_eligible(self, subdivision_id): 
     """Are we eligible for sampling taking into account the 90 day windows""" 
     from .models import Subdivision 
     subdivision = Subdivision.objects.get(id=subdivision_id) 
     return True 


    def get_available_subdivisions(self, subdivision_id): 
     """Return all potential subdivisions for a builder in a metro""" 
     from .models import Subdivision 
     subdivision = Subdivision.objects.get(id=subdivision_id) 
     return self.filter(builder_org=subdivision.builder_org, 
          metro=subdivision.metro) 

    def get_available_sampling_subdivisions(self, subdivision_id): 
     """Return Subdivision which are able to participate in metro sampling""" 
     from .models import Subdivision 
     subdivision = Subdivision.objects.get(id=subdivision_id) 
     return self.filter(builder_org=subdivision.builder_org, 
          metro=subdivision.metro, 
          use_sampling = True, 
          use_metro_sampling = True) 

Answer 1

其實，我把is_metro_sample_eligible()上Subdivision，因爲每次調用需要訪問一個實例。

class Subdivision(models.Model): 
    def is_metro_sample_eligible(self): 
     """Are we eligible for sampling taking into account the 90 day windows""" 
     #TODO do something useful here and return true or false 
     return True 

然後我想無論是移動get_available_subdivisions()和get_available_sampling_subdivisions()到您的builder_org模型

from .models import Subdivision 

class BuilderOrg(models.Model): 
    #whatever you have goes here 
    def get_available_subdivisions(self, metro): 
     """Return all potential subdivisions for a builder in a metro""" 
     return Subdivision.objects.filter(builder_org=self, 
              metro=metro) 

    def get_available_sampling_subdivisions(self, metro): 
     """Return Subdivision which are able to participate in metro sampling""" 
     return Subdivision.objects.filter(builder_org=self, 
              metro=metro, 
              use_sampling = True, 
              use_metro_sampling = True) 

或離開它的經理，和簽名修改到get_available_subdivisions(self, builder_org, metro)。

理由 - 我可以想象需要打電話get_available_subdivisions()，但實際上並沒有Subdivision已經記住 - 顯然重要的信息是建設者組織和地鐵。