I'm working with a legacy database which uses the MySQL big int so I setup a simple custom model field to handle this:
class BigAutoField(models.AutoField):
def get_internal_type(self):
return "BigAutoField"
def db_type(self):
return 'bigint AUTO_INCREMENT' # Note this won't work with Oracle.
This works fine with django south for the id/pk fields (mysql desc "| id | bigint(20) | NO | PRI | NULL | auto_increment |") but the ForeignKey fields in other models the referring fields are created as int(11) rather than bigint(20).
I assume I have to add an introspection rule to the BigAutoField but there doesn't seem to be a mention of this sort of rule in the documentation (http://south.aeracode.org/docs/customfields.html).
Update: Currently using Django 1.1.1 and South 0.6.2
Update 2: Seems the Django code is responsible.
from django.db.models.fields.related.ForeignKey.db_type():
rel_field = self.rel.get_related_field()
if (isinstance(rel_field, AutoField) or
(not connection.features.related_fields_match_type and
isinstance(rel_field, (PositiveIntegerField,
PositiveSmallIntegerField)))):
return IntegerField().db_type()
As I am overloading AutoField isinstance is returning True and it is defaulting to IntegerField. Guess I will have to copy the AutoField code and do it that way . . .