Django：模型上次修改日期和修改计数 [英] Django: models last mod date and mod count

问题描述

我有一个名为 Blog 的Django模型。

I have a django model called Blog.

我想在当前模型中添加一个针对last_modified_date的字段。我知道如何设置默认值，但是我希望通过管理界面修改博客条目时可以自动更新默认值。

I'd like to add a field to my current model that is for last_modified_date. I know how to set a default value, but I would like somehow for it to get automatically updated anytime I modify the blog entry via the admin interface.

是否有某种方法可以在保存每个管理站点时将此值强制为当前时间？

Is there some way to force this value to the current time on each admin site save?

也可以是否有某种方法可以添加 mod_count 字段，并在每次修改管理站点博客条目时自动计算该字段？

Also would there be some way to add a mod_count field and have it automatically calculated on each modify of the admin site blog entry?

推荐答案

在模型中创建 DateTimeField 。每次保存时都要更新。这要求您使用 auto_now_add 选项：

Create a DateTimeField in your model. Have it update whenever it is saved. This requires you to use the auto_now_add option:

class DateTimeField([auto_now=False, auto_now_add=False, **options])

DateTimeField .auto_now_add¶

DateTimeField.auto_now_add¶

每次保存对象时自动将字段设置为现在。有用的
用于最后修改的时间戳。注意
始终使用当前日期。
不仅仅是
可以覆盖的默认值。

Automatically set the field to now every time the object is saved. Useful for "last-modified" timestamps. Note that the current date is always used; it's not just a default value that you can override.

它应该看起来像这样：

class Message(models.Model):
    message = models.TextField()
    active = models.BooleanField(default=True)
    created_at = models.DateTimeField(auto_now_add=True)

< a href = http://docs.djangoproject.com/en/dev/ref/models/fields/ rel = nofollow noreferrer>模型字段引用

第二部分，我认为您必须重载

For the second part, I think you have to overload

ModelAdmin.save_model(self, request, obj, form, change)

如James Bennett所述此处。它看起来像这样：

As James Bennett describes here. It will look something like this:

class EntryAdmin(admin.ModelAdmin):

def save_model(self, request, obj, form, change):
    if change:
        obj.change_count += 1
    obj.save()

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