Question

I have a Django model where I’m importing a number of items:

from django.db import models
from mcif.models.import_profile import ImportProfile
from mcif.models.import_file import ImportFile
from mcif.models.import_bundle import ImportBundle
from mcif.models.customer import Customer
#from mcif.models.account_import import AccountImport
from mcif.models.csv_row import CSVRow
import csv, cStringIO

It works fine, but when I uncomment that line that’s commented, I get this:

Traceback (most recent call last):
  File "./manage.py", line 11, in <module>
    execute_manager(settings)
  File "/usr/lib/pymodules/python2.6/django/core/management/__init__.py", line 438, in execute_manager
    utility.execute()
  File "/usr/lib/pymodules/python2.6/django/core/management/__init__.py", line 379, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/usr/lib/pymodules/python2.6/django/core/management/base.py", line 191, in run_from_argv
    self.execute(*args, **options.__dict__)
  File "/usr/lib/pymodules/python2.6/django/core/management/base.py", line 220, in execute
    output = self.handle(*args, **options)
  File "/usr/lib/pymodules/python2.6/django/core/management/base.py", line 351, in handle
    return self.handle_noargs(**options)
  File "/usr/lib/pymodules/python2.6/django/core/management/commands/shell.py", line 18, in handle_noargs
    loaded_models = get_models()
  File "/usr/lib/pymodules/python2.6/django/db/models/loading.py", line 167, in get_models
    self._populate()
  File "/usr/lib/pymodules/python2.6/django/db/models/loading.py", line 64, in _populate
    self.load_app(app_name)
  File "/usr/lib/pymodules/python2.6/django/db/models/loading.py", line 78, in load_app
    models = import_module('.models', app_name)
  File "/usr/lib/pymodules/python2.6/django/utils/importlib.py", line 35, in import_module
    __import__(name)
  File "/home/jason/projects/mcifdjango/mcif/models/__init__.py", line 5, in <module>
    from mcif.models.account_import import AccountImport
  File "/home/jason/projects/mcifdjango/mcif/models/account_import.py", line 2, in <module>
    from mcif.models.generic_import import GenericImport
  File "/home/jason/projects/mcifdjango/mcif/models/generic_import.py", line 6, in <module>
    from mcif.models.account_import import AccountImport
ImportError: cannot import name AccountImport

Why doesn’t Django like this one particular file?

(I can load AccountImport by itself on the console just fine.)

Also, here’s AccountImport if it helps to see it:

from django.db import models
from mcif.models.generic_import import GenericImport

class AccountImport(models.Model):

    id = models.BigIntegerField(primary_key=True)
    generic_import = models.ForeignKey(GenericImport)
    is_entirely_international = models.IntegerField()
    is_queued = models.IntegerField()
    created_at = models.DateTimeField()
    updated_at = models.DateTimeField()

    class Meta:
        db_table = u'account_import'
        app_name = 'mcif'

And GenericImport:

from django.db import models
from mcif.models.import_profile import ImportProfile
from mcif.models.import_file import ImportFile
from mcif.models.import_bundle import ImportBundle
from mcif.models.customer import Customer
from mcif.models.csv_row import CSVRow
import csv, cStringIO

class GenericImport(models.Model):

    class Meta:
        db_table = u'generic_import'
        app_name = 'mcif'

    id = models.BigIntegerField(primary_key=True)
    import_profile = models.ForeignKey(ImportProfile)
    import_file = models.ForeignKey(ImportFile)
    notes = models.TextField()
    start_time = models.DateTimeField()
    end_time = models.DateTimeField()
    active = models.IntegerField()
    created_at = models.DateTimeField()
    updated_at = models.DateTimeField()
    unsavable_rows = models.TextField()
    import_bundle = models.ForeignKey(ImportBundle)
    is_queued = models.IntegerField()

    @classmethod
    def last(cls):
        all = GenericImport.objects.all()
        return all[len(all) - 1]

    def process(self):
        for line in self.import_file.file.split("\n")[:30]:
            f = cStringIO.StringIO(line)
            row = CSVRow()
            row.array = next(csv.reader(f))
            row.generic_import = self
            row.process()
            f.close()

    def specific_import(self):
        for model_name in ['TransactionImport', 'AccountImport']:
            specific_imports = eval(model_name + '.objects.filter(generic_import__pk=5)')
            if len(specific_imports) > 0:
                return specific_imports[0]
        return False

Answer 1

You have a circular import – mcif.models.generic_import and mcif.models.account_import are trying to import each other.

Remember that Python is not Java, and is quite happy to have multiple classes in a single file, especially if they’re closely related like these two seem to be. Put them both in a single mcif.models file.