Question

这是我的models.py：

class Notification(models.Model):
    user = models.ForeignKey(User)
    createdAt = models.DateTimeField(auto_now_add=True, blank=True)
    read = models.BooleanField(default=False, blank=True)

    class Meta:
        abstract = True

class RegularNotification(Notification):
    message = models.CharField(max_length=150)
    link = models.CharField(max_length=100)

class FNotification(Notification):
    # same as Notification
    pass

当我python manage.py makemigrations时，这就是它所说的：

Migrations for 'CApp':
  0019_auto_20151202_2228.py:
    - Create model RegularNotification
    - Create model FNotification
    - Remove field user from notification
    - Add field f_request to userextended
    - Delete model Notification

首先，它说Remove field user from notification很奇怪，因为user仍然在我的Notiication模型中（所以如果有人能弄清楚为什么它说它说'＆＃ 39;从通知＆＃39;中删除字段用户，这会很棒！）但是，当我继续前进并尝试python manage.py migrate时，我收到此消息：

Applying CMApp.0019_auto_20151202_2228... OK
The following content types are stale and need to be deleted:

    CApp | notification

Any objects related to these content types by a foreign key will also
be deleted. Are you sure you want to delete these content types?
If you're unsure, answer 'no'.

    Type 'yes' to continue, or 'no' to cancel: no

我输入了no。但这究竟是什么意思，为什么我收到这条消息，我该怎么做才能让我不要求这条消息？

Answer 1

删除/删除模型并进行迁移时会触发您收到的消息。

在大多数情况下，您可以安全地删除它们。但是，在某些情况下，这可能会导致数据丢失。如果其他模型具有已删除模型的外键，则这些对象也将被删除。

Here's the django ticket that requests to make deleting stale content types safer.

修改

正如@ x-yuri指出的那样，此票证已经修复并已在Django 1.11中发布。

获取＆＃34;以下内容类型陈旧，需要删除＆＃34;当试图进行迁移时。这意味着什么，我该如何解决？

1 个答案: