Fixed -- Fixed an example of using routers in multiple databases docs.
Make sure that AuthRouter includes ContentType in the same database.
@@ -301,44 +301,51 @@ databases::
}
Now we'll need to handle routing. First we want a router that knows to
-send queries for the ``auth`` app to ``auth_db``::
+send queries for the ``auth`` and ``contenttypes`` apps to ``auth_db``
+(``auth`` models are linked to ``ContentType``, so they must be stored in the
+same database)::
class AuthRouter:
"""
A router to control all database operations on models in the
- auth application.
+ auth and contenttypes applications.
"""
+ route_app_labels = {'auth', 'contenttypes'}
+
def db_for_read(self, model, **hints):
"""
- Attempts to read auth models go to auth_db.
+ Attempts to read auth and contenttypes models go to auth_db.
"""
- if model._meta.app_label == 'auth':
+ if model._meta.app_label in self.route_app_labels:
return 'auth_db'
return None
def db_for_write(self, model, **hints):
"""
- Attempts to write auth models go to auth_db.
+ Attempts to write auth and contenttypes models go to auth_db.
"""
- if model._meta.app_label == 'auth':
+ if model._meta.app_label in self.route_app_labels:
return 'auth_db'
return None
def allow_relation(self, obj1, obj2, **hints):
"""
- Allow relations if a model in the auth app is involved.
+ Allow relations if a model in the auth or contenttypes apps is
+ involved.
"""
- if obj1._meta.app_label == 'auth' or \
- obj2._meta.app_label == 'auth':
+ if (
+ obj1._meta.app_label in self.route_app_labels or
+ obj2._meta.app_label in self.route_app_labels
+ ):
return True
return None
def allow_migrate(self, db, app_label, model_name=None, **hints):
"""
- Make sure the auth app only appears in the 'auth_db'
- database.
+ Make sure the auth and contenttypes apps only appear in the
+ 'auth_db' database.
"""
- if app_label == 'auth':
+ if app_label in self.route_app_labels:
return db == 'auth_db'
return None
