Kod do postu o dodawaniu nowej, unikalnej kolumny do istniejącej tabeli w Django znajdujący się pod adresem https://blog.mloza.pl/dodanie-unikalnej-kolumny-do-istniejacej-tabeli-w-django/‎

migration.py

from __future__ import unicode_literals

import common.functions
from django.db import migrations, models

def uniquify_keys_for_events(apps, schema_editor):
    events = apps.get_model("event", "Event").objects.all()
    for event in events:
        event.key = common.functions.generate_random_string_32()
        event.save()

class Migration(migrations.Migration):

    dependencies = [
        ('event', '0002_auto_20170102_1816'),
    ]

    operations = [
        migrations.AddField( # krok 1
            model_name='event',
            name='key',
            field=models.CharField(max_length=32, null=True),
        ),
        migrations.RunPython(uniquify_keys_for_events), # krok 2
        migrations.AlterField( # krok 3
            model_name='event',
            name='key',
            field=models.CharField(max_length=32, default=common.functions.generate_random_string_32, unique=True))
    ]