I. Suppose you have the following model:
class Knight(models.Model):
name = models.CharField(max_length=100)
of_the_round_table = models.BooleanField()
II. Now you add this model to south's schemamigration and migrate:
python manage.py schemamigration myapp --initial
python manage.py migrate myapp
III. You create an entry in the Knight table:
>>> jason = Knight.objects.get(name=”Jason”)
Nothing out of the ordinary here, just the regular routine. However notice the following.
IV-A. Add a new model field (CharField):
class Knight(models.Model):
name = models.CharField(max_length=100)
of_the_round_table = models.BooleanField()
surname = models.CharField(max_length=100) # +
V-A. Write a schemamigration for this new field:
$ python manage.py schemamigration myapp --auto
? The field 'Knight.surname' does not have a default specified, yet is NOT NULL.
? Since you are adding this field, you MUST specify a default
? value to use for existing rows. Would you like to:
? 1. Quit now, and add a default to the field in models.py
? 2. Specify a one-off value to use for existing columns now
BUT
Now let's try step IV and V again but with a BooleanField instead of a CharField
IV-B. Add a new model field (BooleanField):
class Knight(models.Model):
name = models.CharField(max_length=100)
of_the_round_table = models.BooleanField()
has_sword = models.BooleanField() # +
V-B. Write a schemamigration for this new field:
$ python manage.py schemamigration myapp --auto
+ Added field has_sword on registration.Knight
Created 0005_auto__add_field_knight_has_sword.py. You can now apply this migration with: ./manage.py migrate registration
Q1 : Why do I get a different output for adding a BooleanField(V-B) than for adding a CharField(V-A) even though according to the Django docs both these fields have null=False by default?
Q2 : How are you supposed to know which fields will give an output like BooleanField and which ones will give an output like CharField when you apply python manage.py schemamigration myapp --auto to a model in the given circumstance?
I'm using SQlite as RDBMS and Django 1.4 btw.