id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
25687	Document how database backends should monkey patch functions	Josh Smeaton	Kristof Claes	"@dedsm at djangounderthehood brought up that the docs do not currently contain information for how 3rd party backends should be supporting expressions by monkey patching. Let's fix that.

Firebird backend (with connection.vendor == 'firebird') would change Sum like this:

{{{
from django.db.models import Sum

def backend_sum(self, compiler, connection)
    # do stuff

Sum.as_firebird = backend_sum

}}}"	Cleanup/optimization	closed	Documentation	dev	Normal	fixed		davidesousa@…	Accepted	1	0	0	0	0	0