WebSep 24, 2016 · An alternative to prefetching all nested relationships manually, there is also a package called django-auto-prefetching which will automatically traverse related fields on your model and serializer to find all the models which need to be mentioned in prefetch_related and select_related calls. All you need to do is add in the … Webfrom django.db import models from django.db.models import Prefetch for campaign in Campaign.objects.all().prefetch_related(Prefetch("creative_set", queryset=Creative.objects.filter(name__startswith="hoge").order_by("-created_at"), to_attr="creatives")): if len(campaign.creatives) > 0: print(campaign.id, creatives[0].id)

Python 如何使用Django中与预取_相关的函数从两个表中筛选结果_Python_Django …

WebOct 1, 2013 · 7. We have two models (simplified versions): class Contestant (models.Model): email = models.EmailField (max_length=255, unique=True) # plus some other fields @property def total_points (self): return self.points.aggregate (total=Sum ('value')) ['total'] or 0 class Points (models.Model): contestant = models.ForeignKey (Contestant, … WebAug 26, 2024 · This is spookily similar to Nested annotate fields in Django REST Framework serializers, but the accepted answer does what I'm already doing -- calculating it per record in a SerializerMethodField. A not accepted answer describes doing this with prefetch_related not select_related. Since this is DRF, ... lake livingston poa livingston tx

Djangoでprefetch_relatedを便利に使う - Qiita

WebNov 22, 2013 · You can use annotate and F >>> from django.db.models import F >>> users = User.objects.all().annotate(member_from__status=F('member_from__status')) >>> users[0 ... Web我現在與django的預取有關。 舉個例子，讓我們想象一下那些模型 假設我們有幾個客戶，例如 個，但他們購買了很多商品，因此我們有數百萬的購買量。 如果我必須創建一個顯示 … asko valmentaja