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Django 1.4 database token - "cannot import name join"

I am trying to outline my database on django, but I have a strange error in the first steps.

I made a simple db router that did nothing:

'''file /myproject/myapp/routers.py'''
class ShardingRouter(object):

    def db_for_read(self, model, **hints):
        return 'default'

    def db_for_write(self, model, **hints):
        return 'default'

    def allow_relation(self, obj1, obj2, **hints):
        return 'default'

    def allow_syncdb(self, db, model):
        return 'default'

I added in settings.py:

DATABASE_ROUTERS = ['myproject.myapp.routers.ShardingRouter',]

I get this error:

Traceback (most recent call last):
    File "/usr/local/lib/python2.7/dist-packages/django/core/handlers/wsgi.py", line 219, in __call__
    self.load_middleware()
    File "/usr/local/lib/python2.7/dist-packages/django/core/handlers/base.py", line 45, in load_middleware
    mod = import_module(mw_module)
    File "/usr/local/lib/python2.7/dist-packages/django/utils/importlib.py", line 35, in import_module
    __import__(name)
    File "/hosting/myproject/myproject/middleware.py", line 10, in <module>
    from django.contrib.sites.models import Site
    File "/usr/local/lib/python2.7/dist-packages/django/contrib/sites/models.py", line 1, in <module>
    from django.db import models
    File "/usr/local/lib/python2.7/dist-packages/django/db/__init__.py", line 16, in <module>
    router = ConnectionRouter(settings.DATABASE_ROUTERS)
    File "/usr/local/lib/python2.7/dist-packages/django/db/utils.py", line 116, in __init__
    raise ImproperlyConfigured('Error importing database router %s: "%s"' % (klass_name, e))
ImproperlyConfigured: Error importing database router ShardingRouter: "cannot import name connection"

What is the "connection"? What does it mean? Unable to find where the problem is ((

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3 answers

You need to import connectionsinto settings.py:

from django.db import connections

...
...

DATABASE_ROUTERS = ['myproject.myapp.routers.ShardingRouter',]
...
...
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You should take a look at this question: Django routing with multiple databases

BTW, , allow_relation allow_syncdb True, False None, .

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my application name is a blog synchronized with the alais user1 database:

DATABASE_ROUTERS=['routers.BlogRouter']


DATABASES = {

    'default': {

        'ENGINE': 'django.db.backends.mysql', # Add 'postgresql_psycopg2', 'postgresql', 'mysql', 'sqlite3' or 'oracle'.


        'NAME': 'mupltiple_datab_app1',                      # Or path to database file if using sqlite3.

        'USER': 'root',                      # Not used with sqlite3.

        'PASSWORD': 'admin',                  # Not used with sqlite3.

        'HOST': "",                      # Set to empty string for localhost. Not used with sqlite3.

        'PORT': "",                      # Set to empty string for default. Not used with sqlite3.
    },
    'user1':{
        'ENGINE': 'django.db.backends.mysql', # Add 'postgresql_psycopg2', 'postgresql', 'mysql', 'sqlite3' or 'oracle'.

        'NAME': 'mupltiple_datab_app2',                      # Or path to database file if using sqlite3.

        'USER': 'root',                      # Not used with sqlite3.

        'PASSWORD': 'admin',                  # Not used with sqlite3.

        'HOST': "",                        # Set to empty string for localhost. Not used with sqlite3.

        'PORT': "",  


             }

    ,
    'user2':{
             'ENGINE': 'django.db.backends.mysql', # Add 'postgresql_psycopg2', 'postgresql', 'mysql', 'sqlite3' or 'oracle'.

        'NAME': 'mupltiple_datab_app3',                      # Or path to database file if using sqlite3.

        'USER': 'root',                      # Not used with sqlite3.

        'PASSWORD': 'admin',                  # Not used with sqlite3.

        'HOST':"" ,                      # Set to empty string for localhost. Not used with sqlite3.

        'PORT': "" ,  

             }
}

I am sure that there are several unexplored nuances for working with several databases in Django, and I admit that I did not delve into the basic code of this function, but so far everything works as needed. The really impressive part is viewing applications in the admin without errors.

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