django-orm

One of my models is particularily complex. When I try to edit it in Django Admin it performs 1042 queries and takes over 9 seconds to process. I know I can replace a few of the drop-downs with raw_id_fields , but I think the bigger bottleneck is that it's not performing a select_related() as it should. Can I get the admin site to do this? Although dr jimbob's answer makes sense, for my needs, I was able to simply override the get_queryset() method with a one-liner, even selecting a foreign key's foreign key. Maybe this could be helpful to someone. class MyModelAdmin(admin.ModelAdmin): model =

I have two models like this: class User(models.Model): email = models.EmailField() class Report(models.Model): user = models.ForeignKey(User) In reality each model has more fields which are of no consequence to this question. I want to filter all users who have an email which starts with 'a' and have no reports. There will be more .filter() and .exclude() criteria based on other fields. I want to approach it like this: users = User.objects.filter(email__like = 'a%') users = users.filter(<other filters>) users = ??? I would like ??? to filter out users who do not have reports associated with

I want to write a Django query equivalent to this SQL query: SELECT * from user where income >= 5000 or income is NULL. How to construct the Django queryset filter? User.objects.filter(income__gte=5000, income=0) This doesn't work, because it AND s the filters. I want to OR the filters to get union of individual querysets. Lakshman Prasad from django.db.models import Q User.objects.filter(Q(income__gte=5000) | Q(income__isnull=True)) via Documentation hobs Because QuerySets implement the Python __or__ operator ( | ), or union, it just works. As you'd expect, the | binary operator returns a

I need to be able to sort on the aggregate of two annotated columns So I'd like to do something like this: c = c.annotate(metric=Sum('results__metric')) c = c.annotate(metric_prior=Sum('results__metric_prior')) c = c.annotate(variance=F('metric')-F('metric_prior')) #doesn't work, for demonstrative purposes only and then: c = c.order_by('variance') Does anyone know how to accomplish something like the above? Actually, c = c.annotate(variance=F('metric')-F('metric_prior')) works as you would like it to starting with Django 1.8 . Moreover, you can also order by an expression, which means you can

I have a question about how we can filter by SUM of multiple columns. Example: class Foo(models.Model): i1 = models.IntegerField() i2 = models.IntegerField() i3 = models.IntegerField() And I need to filter objects where SUM of i1, i2, i3 is less then 200. I've tried achive it with: Foo.objects.agregate(i_sum=Sum(i1,i2,i3)).filter(i_sum__lt=200) # error Foo.objects.agregate(i_sum=Sum([i1,i2,i3])).filter(i_sum__lt=200) # error Thanks. You can use F() , and with annotation : Foo.objects.annotate(i_sum=F('i1') + F('i2')+ F('i3')).filter(i_sum=200) You can use extra Foo.objects.extra(where=["i1 +

I'm using django-taggit , which handles the attachment of tags to arbitrary content types. I imported a large tag list, which contains many uppercase words, as well as lowercase words. Now, I' trying to get objects of another class containing a set of tags, but I want to compare case insensitively. When I do this: Media.objects.filter(tags__name__in=['tag1', 'tag2']) objects containing e.g. the tag "Tag1" are not found, only those ones with "tag1" or "tag2". Is there any possibility in the django orm to do something like: Media.objects.filter(tags__name__iin=['tag1', 'tag2']) that acts like