From a39db53e0c53fb5ed9b166e8d1e69576fe2527eb Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ren=C3=A9=20Fleschenberg?= Date: Wed, 6 Nov 2019 15:09:14 +0100 Subject: [PATCH] [2.2.x] Replaced 'n_' prefix with 'number_of_' in docs/topics/db/queries.txt. Backport of 367634f976ab43db93321bf4eb898449b670e291 from master --- docs/topics/db/queries.txt | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/docs/topics/db/queries.txt b/docs/topics/db/queries.txt index bcdaaea359..4fdd20db12 100644 --- a/docs/topics/db/queries.txt +++ b/docs/topics/db/queries.txt @@ -40,8 +40,8 @@ models, which comprise a Weblog application: pub_date = models.DateField() mod_date = models.DateField() authors = models.ManyToManyField(Author) - n_comments = models.IntegerField() - n_pingbacks = models.IntegerField() + number_of_comments = models.IntegerField() + number_of_pingbacks = models.IntegerField() rating = models.IntegerField() def __str__(self): @@ -625,20 +625,20 @@ than pingbacks, we construct an ``F()`` object to reference the pingback count, and use that ``F()`` object in the query:: >>> from django.db.models import F - >>> Entry.objects.filter(n_comments__gt=F('n_pingbacks')) + >>> Entry.objects.filter(number_of_comments__gt=F('number_of_pingbacks')) Django supports the use of addition, subtraction, multiplication, division, modulo, and power arithmetic with ``F()`` objects, both with constants and with other ``F()`` objects. To find all the blog entries with more than *twice* as many comments as pingbacks, we modify the query:: - >>> Entry.objects.filter(n_comments__gt=F('n_pingbacks') * 2) + >>> Entry.objects.filter(number_of_comments__gt=F('number_of_pingbacks') * 2) To find all the entries where the rating of the entry is less than the sum of the pingback count and comment count, we would issue the query:: - >>> Entry.objects.filter(rating__lt=F('n_comments') + F('n_pingbacks')) + >>> Entry.objects.filter(rating__lt=F('number_of_comments') + F('number_of_pingbacks')) You can also use the double underscore notation to span relationships in an ``F()`` object. An ``F()`` object with a double underscore will introduce @@ -1049,7 +1049,7 @@ update one field based on the value of another field in the model. This is especially useful for incrementing counters based upon their current value. For example, to increment the pingback count for every entry in the blog:: - >>> Entry.objects.all().update(n_pingbacks=F('n_pingbacks') + 1) + >>> Entry.objects.all().update(number_of_pingbacks=F('number_of_pingbacks') + 1) However, unlike ``F()`` objects in filter and exclude clauses, you can't introduce joins when you use ``F()`` objects in an update -- you can only