blocks|key|751857|text|我最近在came+across+this+problem上。您所做的一切都很好，但是您可以通过创建一个透明地颠倒关系的mixin来进行更多的概括：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|751858|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)
++++...|code-block|syntax|javascript|751859|和|751860|action+=+Action1.object.get(id=1)
event+=+action.get_event|751861|您可能还想将缓存添加到反向关系中|751862|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/questions/9199000/reversing-a-unique-generic-foreign-key-and-returning-an-object-as-opposed-to-a^0|4|O|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@$A|X|B|Y|1|Z]]|C|$]]|$1|D|3|E|5|F|7|10|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|11|8|@]|9|@]|C|$]]|$1|K|3|L|5|F|7|12|8|@]|9|@]|C|$G|H]]|$1|M|3|N|5|6|7|13|8|@]|9|@]|C|$]]|$1|O|3|-4|5|6|7|14|8|@]|9|@]|C|$]]]|P|$Q|$5|R|S|T|C|$U|V]]]]

I recently <a href="https://stackoverflow.com/questions/9199000/reversing-a-unique-generic-foreign-key-and-returning-an-object-as-opposed-to-a">came across this problem</a>. What you have done is fine, but you can generalise it a little bit more by creating a mixin that reverses the relationship transparently:

<pre><code>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)
 ...
</code></pre>

and 

<pre><code>action = Action1.object.get(id=1)
event = action.get_event
</code></pre>

You might want to add caching to the reverse relationship too

blocks|key|535451|text|如果object不存在，则使用.get()返回raise；如果object不存在，则使用.first()返回None。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|535452|Name+events_relation是区分event和events的一种优雅方式。|535453|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')+#+Important

class+Action1(models.Model):
++++events_relation+=+generic.GenericRelation(Event)

++++@property
++++def+event(self):
++++++++#+Return+the+object+in+exists
++++++++#+else+None+
++++++++return+self.events_relation.first()|code-block|syntax|javascript|535454|entityMap^0|F|6|18|8|0|5|F|N|5|T|6|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]|$9|R|A|S|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|T|8|@$9|U|A|V|B|C]|$9|W|A|X|B|C]|$9|Y|A|Z|B|C]]|D|@]|E|$]]|$1|H|3|I|5|J|7|10|8|@]|D|@]|E|$K|L]]|$1|M|3|-4|5|6|7|11|8|@]|D|@]|E|$]]]|N|$]]

Use <code>.get()</code> return raise if object doesn't exist, <code>.first()</code> return None if object doesn't exist.

Name <code>events_relation</code> is an elegant way to differentiate <code>event</code> from <code>events</code>.

<pre class="lang-py prettyprint-override"><code>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') # Important

class Action1(models.Model):
 events_relation = generic.GenericRelation(Event)

 @property
 def event(self):
 # Return the object in exists
 # else None 
 return self.events_relation.first()
</code></pre>

I need to set up one-to-one relation which must also be generic. May be you can advice me a better design. So far I came up to the following models

<pre><code>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() # &lt;&lt;&lt;&lt;&lt;&lt; Is this reasonable?

class Action2(models.Model):...
</code></pre>

In Django Admin in event list I want to collect all actions, and from there I want go to admin pages for actions. Is it possible to avoid creating <code>event</code> property in the action models? Is there a better solution? It would be nice to combine the field <code>events</code> and the property <code>event</code> in a single definition. The project I am working with uses Django 1.1

Generic one-to-one relation in Django

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我需要设置一对一的关系，这也必须是通用的。也许你可以建议我一个更好的设计。到目前为止，我提出了以下模型class Event(models.Model):    # skip event related fields...    content_type      = models.ForeignKey(Content...

问Django中的泛型一对一关系
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