如何将模型实例添加到Django查询集？ [英] How to add an model instance to a django queryset?

问题描述

django查询集的行为似乎类似于python列表。

It seems like a django queryset behaves somehow like a python list.

但是据我所知，它不支持列表的.append（）方法。

But it doesn't support list's .append() method as I know.

我想做的事情是：

from my_django_app.models import MyModel

queryset = MyModel.objects.none()
queryset.append(MyModel.objects.first())      ## no list's .append() method!

是否可以将模型实例添加到现有查询集中？

Is there any way to add an model instance to an existing queryset?

推荐答案

您还可以使用 | 运算符创建联合：

You can also use the | operator to create a union:

queryset = MyModel.objects.none()
instance = MyModel.objects.first()
queryset |= MyModel.objects.filter(pk=instance.pk)

但是请注意，这将根据数量生成不同的查询这样添加的项目数量，使已编译查询的缓存效率低下。

But be warned that this will generate different queries depending on the number of items you append this way, making caching of compiled queries inefficient.

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