'A helper for subclasses overriding _db_type_for_alter_column:
Remove the check constraint from the type string for PositiveInteger
and PositiveSmallInteger fields.
@param klass: The type of the child (required to allow this to be used when it is subclassed)
@param field: The field to generate type for'

def _db_positive_type_for_alter_column(self, klass, field):

    super_result = super(klass, self)._db_type_for_alter_column(field)
    if isinstance(field, (models.PositiveSmallIntegerField, models.PositiveIntegerField)):
        return super_result.split('    ', 1)[0]
    return super_result
