columns were not added/created to my database table (postgresql) after makemigrations/migrate

Atsunori Kaneshige

unread,

Feb 5, 2019, 9:32:52 PM2/5/19

to Django users

Hi, Django masters!

My app has simple models.py

just two fields like below.

#models.py

class List(models.Model):

item = models.CharField(max_length=200)

completed = models.BooleanField(default=False)

#migration 0001

class Migration(migrations.Migration):

initial = True

dependencies = [

]

operations = [

migrations.CreateModel(

name='List',

fields=[

('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),

('item', models.CharField(max_length=200)),

('completed', models.BooleanField(default=False)),

],

),

]

and after makemigrations/migrate, the app was working no problem.

Then, I wanted to try adding two more fields.

#new models.py

class List(models.Model):

item = models.CharField(max_length=200)

completed = models.BooleanField(default=False)

created_at = models.DateTimeField('date', auto_now_add=True, null = True)

updated_at = models.DateTimeField('update', auto_now=True, null = True)

#migrations 0002

class Migration(migrations.Migration):

dependencies = [

('pages', '0001_initial'),

]

operations = [

migrations.AddField(

model_name='list',

name='created_at',

field=models.DateTimeField(auto_now_add=True, null=True, verbose_name='date'),

),

migrations.AddField(

model_name='list',

name='updated_at',

field=models.DateTimeField(auto_now=True, null=True, verbose_name='update'),

),

]

Django doc says that I need to add 'null = True' because I am using postgresql as my database.

Without 'null = True', the program throws an error saying that column pages_list.created_at doesn't exist etc. when I try to see the web page.

But, with 'null = True', I successfully did makemigration and migrate, then web page showed up without any problem.

But, when I go to admin, I could not find any fields that I though I created.

I also looked at the table in my postgresql, but again, there are only original columns, but not other two columns.

Do you know how to add new columns by changing models.py??

What should I take care to successfully modify models and add new columns in my database table (postgresql in my case).

I really appreciate your advice!

Looking forward to hearing from you.

Nori

Nitin Kalmaste

unread,

Feb 5, 2019, 9:58:30 PM2/5/19

to django...@googlegroups.com

You need to add python's magic method in order to return something from the models you have created. Also you have to register your models to admin.py file. You can refer Django documents for that.

--
You received this message because you are subscribed to the Google Groups "Django users" group.
To unsubscribe from this group and stop receiving emails from it, send an email to django-users...@googlegroups.com.
To post to this group, send email to django...@googlegroups.com.
Visit this group at https://groups.google.com/group/django-users.
To view this discussion on the web visit https://groups.google.com/d/msgid/django-users/a1d71d4c-1500-4972-af57-dc23f5d1ff20%40googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

Atsunori Kaneshige

unread,

Feb 5, 2019, 11:16:08 PM2/5/19

to Django users

Hi Nitin,

Thank you for your comment.

I did not add any additional class in models.py.

I just added two fields under the same class, List.

class List(models.Model):

item = models.CharField(max_length=200)

completed = models.BooleanField(default=False)

created_at = models.DateTimeField('date', auto_now_add=True, null = True)

updated_at = models.DateTimeField('update', auto_now=True, null = True)

In admin.py, I did not change anything.

#this is my admin.py

from django.contrib import admin

from .models import List

# Register your models here. then go to admin page and re-load

admin.site.register(List)

Why new columns (or in other words, new fields) do not show up in my admin site? Even though I did makemigrations/migrate.