pythonpython-3.xdjangomigrationmakemigrations

I'm getting an error message when making migration to db in django

hello guys I'm doing a django tutorial and i missed a change the instructor did in models.py so i fix it but when trying to make the migration to the db it gives me a code that I don't understand or i don't know what to do, here is what it says:

(tonyto) PS E:\web-dev\Python\Django1\myappito> python manage.py makemigrations

Please select a fix:
 1) Provide a one-off default now (will be set on all existing rows with a null value for this column)
 2) Quit, and let me add a default in models.py

they way it was name: models.CharField(max_length=100) details: models.CharField(max_length=500)

and this is how i update it name: models.CharField(max_length=100) details: models.CharField(max_length=500) thank you in advance.

Solution

  • This was caused because you're trying to migrate a model field that cannot be null, but since it cannot be null, it needs a default value so that django can replace all the existing rows with the null value of that field.

    You have two options:

    1. Provide the default by hand, and the django it's going to replace all the null values of that field with this

    2. Set a default value in the model, example:

    number = models.IntegerField(default=1)

    string = models.CharField(default='')