单个django queryset得到相邻的项目 [英] Single django queryset to get n adjacent items

问题描述

我正在制作一个无限/连续滚动列表（如twitter），并希望能够导航到特定的项目。找到该项目是直截了当的，但是我需要在之前和之后收到一些项目。

我对这里提出的答案采用了类似的方法：在Django中获取下一个和上一个对象

  before = list（revers（models.MyModel.objects.filter（pk__lt = pk）.order_by（' -  pk'）[：10]））
 after = list（models.MyModel.objects.filter（pk__gte = pk）.order_by（'pk'）[：11]）$ ​​b $ b objects = before + after 
  / pre> 
 
 
有没有办法将这些组合成一个查询？
 
 
 
我不能简单地组合两个与 | 运算符，如 before |之后而没有列表 /  reverse ，因为片必须先到。我也不能像 pk__lt = pk + 10，pk__gt = pk-10 这样的东西，因为对象可能被删除。
 
 
 
对于一个更复杂的例子，如果我用除主键之外的东西订购，我需要先用另一个查询来获取对象：
  object = get_object_or_404（models.MyModel，pk = pk）
 before = list（revers（models.MyModel.objects.filter（pk__lt = object.other_key）.order_by（' -  other_key '）[：10]））
 after = list（models.MyModel.objects.filter（pk__gte = object.other_key）.order_by（'other_key'）[：11]）$ ​​b $ b objects = before +之后
  
同样，是否可以使用单个查询完成相同的事情？
解决方案
我曾经遇到过类似的问题，并以这里描述：定义描述对象的顺序的SQL变量，然后由t帽子。但是，这是纯SQL。我不知道有没有办法使用Django ORM。
 
I'm making an "infinite"/continuous scrolling list (like twitter) and want to be able to navigate to a specific item. Finding the item is straight forward, but I need to get a few items before and after it.

I'm using a similar approach to the answers suggested here: Getting next and previous objects in Django
before = list(reversed(models.MyModel.objects.filter(pk__lt=pk).order_by('-pk')[:10]))
after = list(models.MyModel.objects.filter(pk__gte=pk).order_by('pk')[:11])
objects = before + after
Is there any way to combine these into the one query?

I can't simply combine the two with the | operator, such as before | after and without list/reverse, as the slice must come first. I also can't do something like pk__lt=pk+10, pk__gt=pk-10 as objects may be deleted.

For a more complex example, if I was ordering by something other than the primary key I'd need to grab the object first with yet another query:
object = get_object_or_404(models.MyModel, pk=pk)
before = list(reversed(models.MyModel.objects.filter(pk__lt=object.other_key).order_by('-other_key')[:10]))
after = list(models.MyModel.objects.filter(pk__gte=object.other_key).order_by('other_key')[:11])
objects = before + after
Likewise, is it possible to accomplish the same thing with a single query?
解决方案
I once had a similar problem and solved it the way described here: defining an SQL-variable that describes the objects' order, and then ordering by that. However, that's plain SQL. I don't know if there's a way using the Django ORM.

                        
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