Django Migration gives an error with OneToOneField

I am working on an application with two databases and two different dbRouters.  On migrating a model with a OneToOneField I get the following error :

django.db.utils.OperationalError: (1824, "Failed to open the referenced table 'auth_user'")

The auth dbRouter is for the [auth, sessions, contenttypes, admin] apps while the Redford dbRouter is for the main app.

Below is the code for the routers : 

auth dbRouter 

class AuthRouter:
    """
    A router to control all database operations on models in the
    auth and contenttypes applications.
    """
    route_app_labels = ('auth', 'contenttypes', 'sessions', 'admin')

    def db_for_read(self, model, **hints):
        """
        Attempts to read auth and contenttypes models go to auth_db.
        """
        if model._meta.app_label in self.route_app_labels:
            return "default"
        return False

    def db_for_write(self, model, **hints):
        """
        Attempts to write auth and contenttypes models go to auth_db.
        """
        if model._meta.app_label in self.route_app_labels:
            return "default"
        return False

    def allow_relation(self, obj1, obj2, **hints):
        """
        Allow relations if a model in the auth or contenttypes apps is
        involved.
        """

        if (obj1._meta.app_label in self.route_app_labels or
            obj2._meta.app_label == 'julia' or 'redford'
            ):
            return True
        return None

    def allow_migrate(self, db, app_label, model_name=None, **hints):
        """
        Make sure the auth and contenttypes apps only appear in the
        'auth_db' database.
        """
       
       
        if db == 'default':
            # Migrate Django core app models if current database is home
            if app_label in ('auth','admin','sessions','contenttypes'):
                return True            
            
            else:
                return False
           
                # Non Django core app models should not be migrated if database is home
        # Other database should not migrate Django core app models            
       
        elif app_label in ['auth','admin','sessions','contenttypes']:
            return False
        # Otherwise no opinion, defer to other routers or default database
        return None

Redford dbRouter

class RedfordRouter(object):
   
    route_app_labels = ('auth', 'contenttypes', 'sessions', 'admin')

    def db_for_read(self, model, **hints):
        if model._meta.app_label == 'redford':
          return 'redford_db'
        return False

    def db_for_write(self, model, **hints):
        if model._meta.app_label == 'redford':
          return 'redford_db'
        return False

    def allow_relation(self, obj1, obj2, **hints):
        if obj1._meta.app_label == 'redford' or obj2._meta.app_label == 'auth':
            return True
        return None

    def allow_migrate(self, db, app_label, model_name=None, **hints):
       
        if db == 'default' or app_label in self.route_app_labels:
            print(db, app_label)
            return None
        elif db == 'redford_db':
            if app_label == 'redford':
                return True
            return False
        return None

The code for the models is as below :

class Employer(models.Model):
     emp_Name = models.OneToOneField(User, on_delete=models.CASCADE,       null=True)
     emp_Company = models.CharField(max_length=100)
     emp_Address = models.CharField(max_length=500)
     emp_Tel = models.CharField(max_length=100)
     emp_JobTitle = models.CharField(max_length=200, null=True)
     emp_JobDesc = models.CharField(max_length=600, null=False)

     def __str__(self):
         return self.emp_Name

Hope we can work it out

regards

Maninder Kumar about.me/maninder.s.kumar

--
You received this message because you are subscribed to the Google Groups "Django users" group.
To unsubscribe from this group and stop receiving emails from it, send an email to django-users+unsubscribe@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/django-users/CABOHK3QsWztSogPx_RzbYcZ46WyK0cHV8JxXBuRSbr2epeQKhg%40mail.gmail.com.