向django模型添加以前不存在的属性

from django.db import models

class MyModel(models.Model):
    existing_property = models.CharField(max_length=100)
    new_property = models.CharField(max_length=100)

python manage.py makemigrations
python manage.py migrate

from django.db import migrations

def update_existing_data(apps, schema_editor):
    MyModel = apps.get_model('your_app_name', 'MyModel')
    for obj in MyModel.objects.all():
        obj.new_property = 'default_value'
        obj.save()

class Migration(migrations.Migration):

    dependencies = [
        ('your_app_name', '0002_auto_20220101_1234'),  # Replace with your previous migration file
    ]

    operations = [
        migrations.RunPython(update_existing_data),
    ]

my_model = MyModel.objects.get(id=1)
my_model.new_property = 'new_value'
my_model.save()

print(my_model.new_property)