I'm working on adding multiple-database support to an application and
am building a custom manager that lets me specify which DATABASE_NAME
to use for a particular model. It looks something like this:
class OtherDatabaseManager(models.Manager):
"""
This Manager lets you set the DATABASE_NAME on a per-model basis.
"""
def __init__(self, database_name, *args, **kwargs):
models.Manager.__init__(self, *args, **kwargs)
self.database_name = database_name
def get_query_set(self):
qs = models.Manager.get_query_set(self)
qs.query.connection = self.get_db_wrapper()
return qs
def get_db_wrapper(self):
from django.db.backends.postgresql_psycopg2.base import DatabaseWrapper
# Monkeypatch the settings file. This is not thread-safe!
old_db_name = settings.DATABASE_NAME
settings.DATABASE_NAME = self.database_name
wrapper = DatabaseWrapper()
wrapper._cursor(settings)
settings.DATABASE_NAME = old_db_name
return wrapper
class MyModel(models.Model):
# ...
objects = OtherDatabaseManager('my_custom_database)
This is not unlike the code here:
http://www.eflorenzano.com/blog/post/easy-multi-database-support-django/
--
One ugliness about this is that it has to monkeypatch the settings
file in order to change the DATABASE_NAME, before passing it to
DatabaseWrapper._cursor(). So my proposal is to change
DatabaseWrapper._cursor() to accept a settings *dictionary* instead of
a settings *object*.
The only place in the Django codebase that calls
DatabaseWrapper._cursor() is BaseDatabaseWrapper.cursor() in
db/backends/__init__.py. That, plus the fact that this method name is
preceded by an underscore, leads me to believe there are no
backwards-incompatibility issues with making this change. But I'm
bringing it up here in case anybody wants to point out problems before
I commit it.
Adrian
--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Django developers" group.
To post to this group, send email to django-developers@googlegroups.com
To unsubscribe from this group, send email to
django-developers+unsubscr...@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/django-developers?hl=en
-~----------~----~----~----~------~----~------~--~---
