Django creating a DateTimeField(auto_now_add) on a populated table

Question

I decided to add a created = Models.DateTimeField(auto_now_add = True) field to a model which already has objects instantiated (without created field of course), and I saved them as initial_data

So now when I run syncdb, I get the error app_model.created may not be NULL since it's trying to load objects without that field.

So how do I fix this? I wish it automatically assigned the time when I call syncdb as object.created. Can I make that?

Thanks for any help!

For some reason I don't want to use migrations.. I stick with syncdb. Probably not very practical :) — jeff, Nov 03 '15 at 23:37

score 1 · Accepted Answer · answered Nov 03 '15 at 23:17

1

I'd use a default value instead of auto_now_add.

from django.utils.timezone import now

class Something(models.Model):
    created = models.DateTimeField(default=now, editable=False)

It also makes your data field timezone aware and uses UTC.

answered Nov 03 '15 at 23:17

C14L

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score 0 · Answer 2 · answered Nov 03 '15 at 23:13

After you add a new field to a model, you need to create and run migrations, by running:

>>> python manage.py makemigrations
>>> python manage.py migrate

In this case, when it try to create the new non-null field, it will ask you if you want to add create a default value in your model or if you want to define a value now, you can choose add a value right there in console. When prompt ask for the value, you can use datetime module, so you can write as value:

datetime.datetime.now()

-or use the timezone.now() isntead of datetime.datetime.now() — KenBuckley, Jun 16 '22 at 15:06

Django creating a DateTimeField(auto_now_add) on a populated table

2 Answers2