Import app model class in another app model

Question

I got 2 app: coworkers and services, each one with its own models.py

In coworkers models.py, I can "from services.models import Services".

When I try to "from coworkers.models import Status" in services models.py, I get this error message:

Traceback (most recent call last): File "/Users/lucas/Documents/projetos/cwk-manager/lib/python2.7/site-packages/Django-1.4.3-py2.7.egg/django/core/management/commands/runserver.py", line 91, in inner_run self.validate(display_num_errors=True) File "/Users/lucas/Documents/projetos/cwk-manager/lib/python2.7/site-packages/Django-1.4.3-py2.7.egg/django/core/management/base.py", line 266, in validate num_errors = get_validation_errors(s, app) File "/Users/lucas/Documents/projetos/cwk-manager/lib/python2.7/site-packages/Django-1.4.3-py2.7.egg/django/core/management/validation.py", line 30, in get_validation_errors for (app_name, error) in get_app_errors().items(): File "/Users/lucas/Documents/projetos/cwk-manager/lib/python2.7/site-packages/Django-1.4.3-py2.7.egg/django/db/models/loading.py", line 158, in get_app_errors self._populate() File "/Users/lucas/Documents/projetos/cwk-manager/lib/python2.7/site-packages/Django-1.4.3-py2.7.egg/django/db/models/loading.py", line 64, in _populate self.load_app(app_name, True) File "/Users/lucas/Documents/projetos/cwk-manager/lib/python2.7/site-packages/Django-1.4.3-py2.7.egg/django/db/models/loading.py", line 88, in load_app models = import_module('.models', app_name) File "/Users/lucas/Documents/projetos/cwk-manager/lib/python2.7/site-packages/Django-1.4.3-py2.7.egg/django/utils/importlib.py", line 35, in import_module import(name) File "/Users/lucas/Documents/projetos/cwk-manager/cwk-manager/cwk_manager/coworkers/models.py", line 2, in from services.models import Services File "/Users/lucas/Documents/projetos/cwk-manager/cwk-manager/cwk_manager/services/models.py", line 5, in class Services(models.Model): File "/Users/lucas/Documents/projetos/cwk-manager/cwk-manager/cwk_manager/services/models.py", line 11, in Services status = models.ForeignKey(Status) NameError: name 'Status' is not defined

--

coworker models.py

from django.db import models
from services.models import Services

class Status(models.Model):
    status_name = models.CharField(max_length=50)
    status_description = models.TextField(blank=True, null=True)

    class Meta:

        verbose_name = "Status"
        verbose_name_plural = "Status"

    def __unicode__(self):
        return self.status_name

services models.py

from django.db import models
from coworkers.models import Status

# This table contains all the information about plans and other general services provided.
class Services(models.Model):
    service_name = models.CharField(max_length=100)
    service_description = models.TextField(blank=True, null=True)
    service_price = models.DecimalField(max_digits=7, decimal_places=2, blank=True, null=True)
    creation_date = models.DateField(auto_now_add=True)
    last_update = models.DateField(auto_now=True)
    status = models.ForeignKey(Status)

    class Meta: 

        verbose_name = "Services"
        verbose_name_plural = "Services"

    def __unicode__(self):
        return self.service_name

-- Can someone help me to see what I am doing wrong?

Thanks in advance!

Answer 1

This is caused by circular import in Python. You can use this syntax:

status = models.ForeignKey('coworkers.models.Status')

Django will determine model using this path so you don't need to import Status.

Another solution in your case would be to delete 2nd import statement in coworker.models because Services doesn't seem to be used in this file.