Django-获取外键对象列表 [英] Django- getting a list of foreign key objects

问题描述

让我们说我有以下模型：

Lets say I have the following models:

class ParentModel(models.Model):
    name = models.CharField()
    child = models.ForeignKey("ChildModel")

class ChildModel(models.Model):
    name = models.CharField()

现在，鉴于ParentModels上的某些过滤器，我想检索所有子模型的列表。我试过了：

Now, given some filter on ParentModels, I want to retrieve a list of all children models. I have tried:

children = ParentModel.objects.filter(name__startswith='A').values_list('child', flat=True)

但是这将返回ChildModel id的列表，而不是完整的对象。是否有一个queryset函数可以完成我想做的事情，还是需要使用返回的ID编写其他过滤器查询？即-而不是：

However this returns a list of ChildModel ids, rather than the full objects. Is there a queryset function that will accomplish what I am trying to do or do I need to write an additional filter query using the returned ids? I.e.- instead of:

children => [51L, 53L, 54L]

我要：

children => [<ChildModel: ChildModel Object>, <ChildModel: ChildModel Object>, <ChildModel: ChildModel Object>]

推荐答案

您可以在 __ in 中使用子查询：

You can use a subquery with __in:

Child.objects.filter(parent__in=Parent.objects.filter(name__startswith='A'))

（请注意，您的命名在这里有点奇怪：通常，孩子是具有外键的孩子，因为它假定父母可以有多个孩子。）

(Note, your naming is a bit odd here: usually the child is the one with the foreign key, since it assumes that a parent can have multiple children.)

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