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Replaced 'n_' prefix with 'number_of_' in docs/topics/db/queries.txt.

This commit is contained in:
René Fleschenberg 2019-11-06 15:09:14 +01:00 committed by Mariusz Felisiak
parent cc5622ec8c
commit 367634f976

View File

@ -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
@ -1051,7 +1051,7 @@ 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