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In django do models have a default timestamp field?

Posted by: admin November 30, 2017 Leave a comment

Questions:

In django – is there a default timestamp field for all objects? That is, do I have to explicitly declare a ‘timestamp’ field for ‘created on’ in my Model – or is there a way to get this automagically?

Answers:

No such thing by default, but adding one is super-easy. Just use the auto_now_add parameter in the DateTimeField class:

created = models.DateTimeField(auto_now_add=True)

You can also use auto_now for an ‘updated on’ field. Check their behaviour in the doc.

A model with both fields will look like this:

class MyModel(models.Model):
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

Questions:
Answers:

Automagically doesn’t sound like something django would do by default. It wouldn’t force you to require a timestamp.

I’d build an abstract base class and inherit all models from it if you don’t want to forget about the timestamp / fieldname, etc.

class TimeStampedModel(models.Model):
     created_on = models.DateTimeField(auto_now_add=True)

     class Meta:
         abstract = True

It doesn’t seem like much to import wherever.TimeStampedModel instead of django.db.models.Model

class MyFutureModels(TimeStampedModel):
    ....

Questions:
Answers:

If you are using django-extensions (which is a good app for adding functionality to the django-admin.py command line helper) you can get these model fields for free by inheriting from their TimeStampedModel or using their custom TimeStamp fields

Questions:
Answers:

You can try django-extensions

if you want to use time-stamp abstract model

from django_extensions.db.models import TimeStampedModel

class A(TimeStampedModel):
   ...

It has other abstract models. you can use that too.