Commit fa4ac6f8 authored by Luke Plant's avatar Luke Plant
Browse files

[1.2.X] Some small fixes to DB optimization docs. 

Backport of [15122] from trunk.

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.2.X@15123 bcc190cf-cafb-0310-a4f2-bffc1f526a37
parent 2d854539

docs/topics/db/optimization.txt

+3 −2
Original line number Diff line number Diff line
@@ -191,7 +191,7 @@ Don't overuse ``count()`` and ``exists()`` 


If you are going to need other data from the QuerySet, just evaluate it.



For example, assuming an Email class that has a ``body`` attribute and a

For example, assuming an Email model that has a ``body`` attribute and a

many-to-many relation to User, the following template code is optimal:



.. code-block:: html+django
@@ -212,7 +212,8 @@ many-to-many relation to User, the following template code is optimal: 


It is optimal because:



 1. Since QuerySets are lazy, this does no database if 'display_inbox' is False.

 1. Since QuerySets are lazy, this does no database queries if 'display_inbox'

    is False.



 #. Use of ``with`` means that we store ``user.emails.all`` in a variable for

    later use, allowing its cache to be re-used.