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
18275	documentation: invalid foreign key and select_related	adriannye@…	nobody	"Let's say Book has a foreign key to Author.
If there is a invalid id in the Author field of any Book instance, then these two queries get a different set
of Book instances:

Book.objects.all()
Book.objects.select_related('author').all()

The second query will omit the Book objects that have an author field that points nowhere.
This surprised me since I thought of select_related as only ADDING information to a query.  In this situation it also REMOVES information.

Invalid keys can happen with a database that does not have referential integrity checking like mysql with MyISAM."	Uncategorized	closed	Documentation	1.3	Normal	wontfix			Unreviewed	0	0	0	0	1	0