Question

我在自己的应用程序中遇到DoesNotExist错误。关键是我不太理解为什么在我已经处理此错误时会抛出该错误：

import socket

from django.core.exceptions import ObjectDoesNotExist
from django.db import Models

class MyClass(models.Model):
    name = models.CharField(max_length=250, default=socket.gethostname(), unique=True)
    @staticmethod
    def update_some_list(some_list):
        for some_item in some_list:
            try:
                MyClass.objects.get(name=some_item)
            except ObjectDoesNotExist:  # I also tried with MyClass.DoesNotExist
                MyClass.objects.create(name=some_item)

这里的意思是，当我遇到这段代码时，我有一些“模块级” DosNotExist被扔掉了，好像这个try / except块从未被击中：

Traceback (most recent call last):
  File "/app/backend/shared/models.py", line 201, in update_some_list
    MyClass.objects.get(name=some_item)
  File "/usr/lib/python3.6/site-packages/django/db/models/manager.py", line 82, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File "/usr/lib/python3.6/site-packages/django/db/models/query.py", line 399, in get
    self.model._meta.object_name
shared.models.DoesNotExist: MyClass matching query does not exist.

Answer 1

考虑使用QuerySet.get_or_create，它将消除上述问题。

MyClass.objects.get_or_create(name=some_item)

还请注意，如果您在@staticmethod内部访问类，则将其更新为@classmethod是有意义的。另外，在您遇到的问题中：

from django.db import Models

而不是从django.db导入模型

Django在DosNotExist上的try / except仍然会抛出它

1 个答案: