Question

i have issue with the DB Router on Django 1.4 (python 2.6). I have follow the documentation (https://docs.djangoproject.com/en/dev/topics/db/multi-db/#automatic-database-routing) but when i run my server i have this following error message:

django.core.exceptions.ImproperlyConfigured: Error importing database router MyDBRouter: "cannot import name connection"

My settings.py

DATABASES = {
    'default': {
        ...
    },
    'other' : {
        ...
    }
}
DATABASE_ROUTERS = ['core.models.MyDBRouter',]

here the db router code :

class MyAppRouter(object):
    def db_for_read(self, model, **hints):
        "Point all operations on myapp models to 'other'"
        if model._meta.app_label == 'myapp':
            return 'other'
        return None

    def db_for_write(self, model, **hints):
        "Point all operations on myapp models to 'other'"
        if model._meta.app_label == 'myapp':
            return 'other'
        return None

    def allow_relation(self, obj1, obj2, **hints):
        "Allow any relation if a model in myapp is involved"
        if obj1._meta.app_label == 'myapp' or obj2._meta.app_label == 'myapp':
            return True
        return None

    def allow_syncdb(self, db, model):
        "Make sure the myapp app only appears on the 'other' db"
        if db == 'other':
            return model._meta.app_label == 'myapp'
        elif model._meta.app_label == 'myapp':
            return False
        return None

I have try to replace None by ‘default’ but it still doesn’t work.

Answer 1

I have solved this probleme by adding “from django.db import connections” on settings.py

151 # Database router                                                                                                                                       
152 from django.db import connections
153 DATABASE_ROUTERS         = ['core.models.MyDBRouter',]

Now the server run fine! But router is just IGNORED by django -> To fix it, never save Router in models ! create new file