django-select-related Questions
3
Solved
I update project from Django 1.6.7 to 1.8.7 and I have got following exception with Django 1.8, although with Django 1.6 it code was right:
In[2]: from apps.route import models
In[3]: models.Trace....
Boorman asked 5/5, 2016 at 9:0
6
Solved
In Django doc:
select_related() "follows" foreign-key relationships, selecting additional related-object data when it executes its query.
prefetch_related() does a separate lookup for ea...
Gracioso asked 6/7, 2015 at 2:31
1
Solved
I have a strange situation. I've done so much reading on avoiding the N+1 problem and have tried prefetching but to no avail. My setup is like this:
Models:
class A(models.Model):
somefield1 = mod...
Burmeister asked 30/9, 2022 at 21:37
4
How does select_related work with a model which has multiple foreign keys? Does it just choose the first one?
class Model:
fkey1, fkey2, fkey3...
The documentation doesn't say anything about this, ...
Illtimed asked 17/1, 2013 at 18:12
3
Solved
I'm trying to figure out how to use select_related or prefetch_related to optimize a query from the other end of a foreign key. For example:
Say I have some models such as the following:
class ...
Lonni asked 29/3, 2014 at 17:39
0
I am trying to build an endpoint for the default django's Group model, which has name and permissions fields:- Here are my view and serializers:-
Serializers.py:-
class GroupSerializer(serializers....
Thrive asked 6/8, 2021 at 13:33
3
Solved
I would like to be able to check if a related object has already been fetched by using either select_related or prefetch_related, so that I can serialize the data accordingly. Here is an example:
...
Debar asked 4/4, 2016 at 12:3
1
Solved
I have seem some examples of how to prefetch_related fields in a forward and backward relationship in Django, but I have doubts about how can this be applied if we want to prefetch all the fields o...
Keelby asked 27/5, 2021 at 9:24
3
Solved
I have two models Article and Blog related using a foreign key. I want to select only blog name while extracting the article.
articles = Articles.objects.all().select_related('blog__name')
The q...
Lemniscus asked 20/2, 2016 at 13:57
3
Solved
I've got an app where users create pages. I want to run a simple DB query that returns how many users have created more than 2 pages.
This is essentially what I want to do, but of course it's not ...
Fable asked 29/6, 2011 at 18:57
1
Solved
I have two models from different apps:
class Measure(models.Model):
date = models.DateTimeField(default="2018-01-23 15:55")
average = models.FloatField(default=0)
class Sensor(models.Model):
m...
Graffito asked 25/2, 2019 at 8:24
2
Solved
I read the documentation and all the related questions here but I haven't properly understood how select_related behaves on chained/multiple foreign keys.
Assume we have the following models:
cl...
Krieg asked 19/9, 2018 at 16:13
4
Solved
I have the following models:
class User(models.Model):
name = models.Charfield()
email = models.EmailField()
class Friendship(models.Model):
from_friend = models.ForeignKey(User)
to_friend ...
Tactic asked 27/10, 2014 at 17:30
1
Solved
I would like to prefetch a model property to a queryset in Django. Is there a way do that ?
Here are the three models:
class Place(models.Model):
name = models.CharField(max_length=200, blank=Tr...
Aerograph asked 17/12, 2017 at 11:28
1
Solved
I have created a OneToOneField(parent) in Child model with related_name='children'. In my views, I used select_related to get the queryset. But in my page the list of children associated to a paren...
Butterball asked 1/8, 2016 at 14:50
1
Solved
I created this simple set of data to illustrate my point. It is a simple model with no further relations to any other model.
I need to group the data above by topicid, find the max date for each...
Tea asked 19/6, 2016 at 14:3
3
Solved
Imagine the following model:
class Parent(Model):
...
class Child(Model)
father = ForeignKey(Parent)
...
Some parents have children, others do not (they're not parents in the real meaning, i...
Osseous asked 4/6, 2010 at 15:29
1
Solved
I have a User model and UserProfile model. In the User model I'd like to order my query so that its in alphabetical order by last_name. Then I'd like to order it by the User_profiles "title" attrib...
Wigwam asked 7/5, 2012 at 19:47
3
Solved
Should entry_set be cached with select_related? My DB is still getting calls even after I use select_related. The pertinent sections
class Alias(models.Model):
achievements = models.ManyToManyFi...
Conium asked 29/6, 2009 at 6:34
2
Solved
I have :
class Award(models.Model) :
name = models.CharField(max_length=100, db_index=True)
class Alias(models.Model) :
awards = models.ManyToManyField('Award', through='Achiever')
class Achie...
Raddle asked 6/9, 2009 at 23:52
2
Solved
I'm getting thousands of these queries when I try to open up a model in the Django admin interface and it's leading to a serious performance issue.
[sql] SELECT ... FROM `auth_user` WHERE `auth_us...
Shifflett asked 15/3, 2012 at 12:26
1
Solved
Is there any way of using get_object_or_404 and select_related together or any other way to achieve the result of using these two together(except from putting it in try/except)??
Cunningham asked 8/7, 2011 at 12:38
1
Solved
In my Django app I want to use select_related() on a QuerySet to "follow" a ForeignKey field, but I only need to access a few of the fields on the "followed" model instance. Can I use the defer() m...
Heavyfooted asked 7/5, 2011 at 4:2
1
I have a simple music schema: Artist, Release, Track, and Song. The first 3 are all logical constructs while the fourth (Song) is a specific instance of an (Artist, Release, Track) as an mp3, wav, ...
Deerdre asked 23/10, 2009 at 7:37
1
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