Do I need to make a migration if I change null and blank values on a Model field?

Question

I have the following model

@python_2_unicode_compatible
class Booking(models.Model):
    session = models.ForeignKey(verbose_name=_('Session'), to=Session, default=None, null=False, blank=False)
    quantity = models.PositiveIntegerField(verbose_name=_('Quantity'), default=1, null=False, blank=False)
    price = models.DecimalField(verbose_name=_('Price'), max_digits=10, decimal_places=2,
                                default=None, null=False, blank=False)
    name = models.CharField(verbose_name=_('Name'), max_length=100, default=None, null=False, blank=False)
    email = models.EmailField(verbose_name=_('Email'), default=None, null=True, blank=True)
    phone_number = models.CharField(verbose_name=_('Phone Number'), max_length=30, default=None, null=True, blank=True)

Say I need to change my email and phone_number fields. I want them to have null=False and blank=False. Do these alterations require a new migration?

Answer 1

Yes they do. null=False requires a change to the database schema itself; blank=False does not, but Django needs a migration anyway so that the migration runner's internal graph of the model state is up to date.

Answer 2

Sure. To check it you can run python manage.py makemigrations --dry-run (the --dry-run doesn't save a new migration file, but shows if it's necessary)