Django级联删除和post_delete信号 [英] Django cascade delete and post_delete signal

问题描述

在我的应用程序中， post_delete 信号记录在特定模型中以及何时将其删除.

In my application post_delete signals being recorded in a specific model and when it was removed.

class A(models.Model):
    ...

class B(models.Model):
    a = models.ForeignKey('A')

class C(models.Model):
    b = models.ForeignKey('B')

def log_delete(sender, instance, **kwargs):
    logging

post_delete.connect(log_delete, sender = A)
post_delete.connect(log_delete, sender = C)

当您删除A实例时，会同时删除B和C实例.如何在django进行级联删除时为子实例禁用信号?

When you delete an instance of A cascade delete occurs removing B and C instances. How can I disable signal for child instances on cascade delete by django?

推荐答案

这不是user2059857所建议的优雅解决方案，但更易于实现:

Not an elegant solution as what user2059857 suggested, but a LOT simpler to implement:

为模型A添加一个字段:

Add a field to model A:

being_deleted = models.BooleanField(default=False)`

在触发模型pre_delete信号时将其设置为True:

Set this to True when A model pre_delete signal is fired:

@receiver(models.signals.pre_delete, sender=A)
def a_pre_delete(sender, instance, **kwargs):
    instance.being_deleted = True
    instance.save()

检查您的A实例的 being_deleted 在子模型的每个 pre_delete 中是否为True，并采取相应的措施.

Check if being_deleted of your A instance is True in every pre_delete of child models and act accordingly.

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