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[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
This commit is contained in:
Luke Plant 2010-12-31 15:48:51 +00:00
parent 2d854539c3
commit fa4ac6f80c
1 changed files with 3 additions and 2 deletions
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docs/topics/db/optimization.txt
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@ -191,7 +191,7 @@ Don't overuse ``count()`` and ``exists()``
If you are going to need other data from the QuerySet, just evaluate it. 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: many-to-many relation to User, the following template code is optimal:
.. code-block:: html+django .. code-block:: html+django
@ -212,7 +212,8 @@ many-to-many relation to User, the following template code is optimal:
It is optimal because: 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 #. Use of ``with`` means that we store ``user.emails.all`` in a variable for
later use, allowing its cache to be re-used. later use, allowing its cache to be re-used.