Using a user-built DB backend

[George Vilches <gav@…>]

Since the DB backend refactoring, creating your own backend package has been easier than ever. Installing your customized backend in the Django source doesn't make sense, so the intention here is to be able to reference the backend somewhere outside the Django source.

This was discussed here with some favorable results on the django-dev list: ​http://groups.google.com/group/django-developers/browse_thread/thread/6bdfac9b1eac8d63/9ef5a73a61671cbd?lnk=gst&q=george+vilches&rnum=1#9ef5a73a61671cbd

[George Vilches <gav@…>]

Adds support for specifying a user backend against r6186.

[George Vilches <gav@…>]

The provided patch allows you to reference the backend in your settings.py file by putting a module path in DATABASE_ENGINE.

An example (assume I have an package in my path called 'db_backends', which contains a package called test1 that contains a fully-involved backend):

#DATABASE_ENGINE = 'mysql'
DATABASE_ENGINE = 'db_backends.test1'
DATABASE_NAME = 'test_db'
DATABASE_USER = 'test_user'

Either of the above DATABASE_ENGINE statements work with this patch. If you provide a package that doesn't exist, Django fails and returns the error message it always has.

[George Vilches <gav@…>]

Sorry, screwed up the example:

#DATABASE_ENGINE = 'mysql' 
DATABASE_ENGINE = 'db_backends.test1' 
DATABASE_NAME = 'test_db' 
DATABASE_USER = 'test_user'

[Russell Keith-Magee]

Like the idea, like the interface - don't like the patch. get_creation_module and get_introspection_module now have a dependence on import_path, a global variable. This should probably be curried into the functions, rather than be left as a global reference.

[George Vilches <gav@…>]

Moved global variables to curried functions.

[George Vilches <gav@…>]

The current patch against r6284 removed the dependence on import path via django.utils.functional.curry.

[Jacob]

(In [6316]) Fixed #5454: settings.DATABASE_BACKEND may now refer to an external package (i.e. one located outside the Django source. Thanks, George Vilches.