[PYTHON] Django's auto_now may not be updated

Django's model has a DateTimeField as its argument

--ʻAuto_now_add: Enter the current time when creating --ʻAuto_add: Update with the current time when saving

There is a convenient function called. Often

class User(models.Model):
     name = models.CharField()
     created = models.DateTimeField(
        auto_now_add=True
     )
     updated = models.DateTimeField(
        auto_now=True
     )

It is defined and used in the form of.

Updated with auto_now

With a model with such a field

user = User.objects.create(name="kasajei")
print(user.created)
>>>Current time
print(user.updated)
>>>Current time
user.name = "kasajei2"
user.save()
print(user.updated)
>>>Saved time

Then, set the current time in updated, and Django will update it with a value without saving. Convenient!

Auto_now, but not updated

However, sometimes, if I thought that it would not be updated, it seems that it will not be updated in the case of specifying the argument with ʻupdate` as follows.

user.name="kasajei3"
user.save(update_fields="name")
print(user.updated)
>>>Not updated! !!

Other,

User.objects.filter(name="kasajei").update(name="kasajei2")
user = User.objects.get(name="kasajei2")
print(user.updated)
>>>Not updated! !!

Etc. will not be updated!

As you can see from the properly issued SQL, I trusted ʻauto_now` too much and didn't notice it for a while.

Since it's ʻauto_now`, I'm wondering if it's okay to update it, but what about it?