Django中的通用一對一關係

Question

我需要建立一對一的關係，它也必須是通用的。也許你可以給我一個更好的設計建議。到目前爲止，我想出了以下型號

class Event(models.Model): 
    # skip event related fields... 
    content_type  = models.ForeignKey(ContentType) 
    object_id   = models.PositiveIntegerField() 
    content_object = generic.GenericForeignKey('content_type', 'object_id') 

    class Meta: 
     unique_together = ('content_type', 'object_id') 

class Action1(models.Model): 
    # skip action1 related fields... 
    events = generic.GenericRelation(Event, content_type_field='content_type', object_id_field='object_id') 

    @property 
    def event(self): 
     return self.events.get() # <<<<<< Is this reasonable? 

class Action2(models.Model):... 

在Django管理在事件列表我要收集所有的行動，並從那裏我想要去管理頁面進行操作。是否有可能避免在動作模型中創建event屬性？有更好的解決方案嗎？在單個定義中將字段events和屬性event組合起來會很好。我正在使用的項目使用Django 1.1

Answer 1

我最近是came across this problem。您所做的一切是好的，但你可以通過創建逆轉透明的關係混入概括它一點點：

class Event(models.Model): 
    content_type  = models.ForeignKey(ContentType) 
    object_id   = models.PositiveIntegerField() 
    content_object = generic.GenericForeignKey('content_type', 'object_id') 

    class Meta: 
     unique_together = ('content_type', 'object_id') 

class EventMixin(object): 
    @property 
    def get_event(self): 
     ctype = ContentType.objects.get_for_model(self.__class__) 
     try: 
      event = Event.objects.get(content_type__pk = ctype.id, object_id=self.id) 
     except: 
      return None 
     return event 

class Action1(EventMixin, models.Model): 
    # Don't need to mess up the models fields (make sure the mixing it placed before models.Model) 
    ... 

和

action = Action1.object.get(id=1) 
event = action.get_event 

你可能想緩存添加到反關係太