如何在Python Django中创建一个新对象，如果它在另外两个类中不存在？

There are two classes in a model- Task and TaskArchives. i need to create a new task if it does not already exist in both Task andTaskArchives. i've tried checking the DoesNotExist exception with an and clause. but it doesn't work. could someone please suggest a different method ??

模型中有两个类 - Task和TaskArchives。我需要创建一个新任务,如果它在Task和TaskArchives中都不存在。我已经尝试使用和子句检查DoesNotExist异常。但它不起作用。有人可以建议一个不同的方法??

for event in events:
        try:
            obj = Task.objects.get(task_id = event['id'])
            obj_archive = TaskArchive.objects.get(task_id = event['id'])

        except Task.DoesNotExist and TaskArchive.DoesNotExist:
            obj = Task.objects.create(
            task_id = event['id'],
            title = event['summary'],
            created_by = User.objects.get(email=event['creator']['email']),
            status = "upcoming",
            due_date = event['start']['dateTime']
            )

Thanks in advance, Reenu.

在此先感谢Reenu。

1 个解决方案

#1

You can try using the QuerySet's exists() function. It returns True if the QuerySet contains any results, and False if not.

您可以尝试使用QuerySet的exists()函数。如果QuerySet包含任何结果,则返回True,否则返回False。

So, for the example above I would write:

所以,对于上面的例子我会写:

if not Task.objects.filter(task_id = event['id']).exists() and
   not TaskArchive.objects.filter(task_id = event['id']).exists:
    # no object satisfying query exists
else:
    # at least one object satisfying query exists

#1