Made the database master router tolerant of router definitions that omit individual routing methods.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@12304 bcc190cf-cafb-0310-a4f2-bffc1f526a37

1 files changed, 5 insertions, 1 deletions

diff --git a/docs/topics/db/multi-db.txt b/docs/topics/db/multi-db.txt
index f1d67bf977..73872e6b53 100644
--- a/docs/topics/db/multi-db.txt
+++ b/docs/topics/db/multi-db.txt
@@ -99,7 +99,7 @@ routing scheme.
 Database routers
 ----------------
 
-A database Router is a class that provides four methods:
+A database Router is a class that provides up to four methods:
 
 .. method:: db_for_read(model, **hints)
 
@@ -141,6 +141,10 @@ A database Router is a class that provides four methods:
     the router has no opinion. This method can be used to determine
     the availability of a model on a given database.
 
+A router doesn't have to provide *all* these methods - it omit one or
+more of them. If one of the methods is omitted, Django will skip that
+router when performing the relevant check.
+
 .. _topics-db-multi-db-hints:
 
 Hints