手动创建Django QuerySet或手动将对象添加到QuerySet [英] manually create a Django QuerySet or rather manually add objects to a QuerySet

问题描述

基本上，我需要一种优雅的方法来执行以下操作：-

Basically I need a graceful way to do the following:-

obj1 = Model1.objects.select_related('model2').get(attribute1=value1)
obj2 = Model1.objects.select_related('model2').get(attribute2=value2)
model2_qs = QuerySet(model=Model2, qs_items=[obj1.model2,obj2.model2])

我可能没有想到正确的方法，但是执行以下操作似乎是非常愚蠢的对我来说：-

I may not be thinking right, but doing something like the following seems infinitely stupid to me.: -

obj1 = Model1.objects.select_related('model2').get(attribute1=value1)
model2_qs = Model2.objects.filter(pk=obj1.model2.pk)

是，我需要结束使用Model2的QuerySet以便以后使用（特别是传递给Django表单）。

Yes, I need to end up with a QuerySet of Model2 for later use (specifically to pass to a Django form).

在上面的第一个代码块中，即使我使用 filter 而不是 get 我显然将拥有Model1的QuerySet。在我的情况下，不一定总是可以进行反向查找。

In the first code block above,even if I use filter instead of get I will obviously have a QuerySet of Model1. Reverse lookups may not always be possible in my case.

推荐答案

如果您只是想创建一个查询集，通过一些在SQL中无法表示的复杂过程进行选择，您可以始终使用 __ in 运算符。

If you're simply looking to create a queryset of items that you choose through some complicated process not representable in SQL you could always use the __in operator.

wanted_items = set()
for item in model1.objects.all():
    if check_want_item(item):
        wanted_items.add(item.pk)

return model1.objects.filter(pk__in = wanted_items)

您显然必须使其适应您的情况，但这至少应该为您提供一个起点。

You'll obviously have to adapt this to your situation but it should at least give you a starting point.

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