有没有更好的方法来计算 Django Viewsets 中的关系？

Question

我在创建视图集、对相关模型中的字段进行计算时遇到问题。我对 Django 很陌生，所以请放轻松。 :)

基本上。我有一个角色模型。还有一个 Raids 模型。 Raids 模型与 Character 具有多对多关系。每个突袭都值得一个价值。我认为我总结的价值观很好。

我的主要问题是，我希望能够计算每个角色的 30、60、90 天和终生出勤率。而我正在挣扎。如果您能提供任何帮助，我将不胜感激。

编辑：我希望得到每个角色的 raid.value 的总和（我已经这样做了，但我不确定是否有更好/更清洁的方法）。此外，困难的部分是试图获得出勤率。所以本质上。我想将一个角色参加的袭击次数 / 总袭击次数（在 4 个不同的时间范围内）分开

models.py

from datetime import timedelta

from django.contrib.auth.models import User
from django.db import models
from django.utils import timezone

...

class Character(models.Model):
    name = models.CharField(
        'Name',
        unique=True,
        primary_key=True,
        max_length=25,
    )

...

class Raid(CreatedModifiedAbstractModel):
    value = models.PositiveSmallIntegerField('DKP Value')
    datetime = models.DateTimeField('Date',auto_created=True)
    characters = models.ManyToManyField(
        Character,
        verbose_name='Attendees',
        related_name='raids',
    )
    not_attendance = models.BooleanField('Not for Attendance',default=False)

views.py

class Dkp(viewsets.ModelViewSet):
    serializer_class = DkpSerializer
    permission_classes = [permissions.IsAuthenticatedOrReadOnly]

    def get_queryset(self, *args, **kwargs):
        date_30 = timezone.now() - timedelta(days=30)
        date_60 = timezone.now() - timedelta(days=60)
        date_90 = timezone.now() - timedelta(days=90)
        all_raids = Raid.objects.filter(not_attendance=False)
        qs = Character.objects.all()
        qs = qs.extra(
            select=all_raids.aggregate(
                raid_30=Count('id', filter=Q(datetime__gte=date_30)),
                raid_60=Count('id', filter=Q(datetime__gte=date_60)),
                raid_90=Count('id', filter=Q(datetime__gte=date_90)),
                raid_life=Count('id'),
            )
        )
        qs = qs.annotate(
            earned_dkp=Coalesce(Sum('raids__value'), 0),
            spent_dkp=Coalesce(Sum('purchases__value'), 0),
            current_dkp=F('earned_dkp') - F('spent_dkp'),
            att_30=Count('raids', filter=(Q(raids__not_attendance=False) & Q(raids__datetime__gte=date_30)), default=0),
            att_60=Count('raids', filter=(Q(raids__not_attendance=False) & Q(raids__datetime__gte=date_60)), default=0),
            att_90=Count('raids', filter=(Q(raids__not_attendance=False) & Q(raids__datetime__gte=date_90)), default=0),
            att_life=Count('raids', filter=Q(raids__not_attendance=False), default=0),
        )
        return qs

序列化器.py

class DkpSerializer(CharacterSerializer):
    current_dkp = serializers.IntegerField(read_only=True)
    earned_dkp = serializers.IntegerField(read_only=True)
    spent_dkp = serializers.IntegerField(read_only=True)
    att_30 = serializers.IntegerField(read_only=True)
    att_60 = serializers.IntegerField(read_only=True)
    att_90 = serializers.IntegerField(read_only=True)
    att_life = serializers.IntegerField(read_only=True)
    raid_30 = serializers.IntegerField(read_only=True)
    raid_60 = serializers.IntegerField(read_only=True)
    raid_90 = serializers.IntegerField(read_only=True)
    raid_life = serializers.IntegerField(read_only=True)
    rate_30 = serializers.IntegerField(read_only=True)
    raids = RaidSerializer(read_only=True, many=True)
    purchases = ItemPurchaseSerializer(read_only=True, many=True)

Answer 1

我的主要问题是，我希望能够计算每个角色的 30、60、90 天和终生出勤率。

import datetime
from django.db.models import Count, Q
date_30 = datetime.datetime.now() + datetime.timedelta(-30)
date_60 = datetime.datetime.now() + datetime.timedelta(-60)
date_90 = datetime.datetime.now() + datetime.timedelta(-90)


Character.objects.annotate(
    raid_30 = Count('raids', filter=Q(raids__datetime__gte=date_30)),
    raid_60 = Count('raids', filter=Q(raids__datetime__gte=date_60)),
    raid_90 = Count('raids', filter=Q(raids__datetime__gte=date_90)),
    raid_life = Count('raids')
)

我希望得到每个角色的 raid.value 的总和（我已经这样做了，但我不确定是否有更好/更清洁的方法）。

from django.db.models import Sum
Character.objects.annotate(
    raid_value = Sum('raids__value')
)

我想除以一个角色参加的突袭次数/总的突袭次数（在 4 个不同的时间范围内）

raids_count = Raid.objects.aggregate(
    raid_30 = Count('pk', filter=Q(datetime__gte=date_30)),
    raid_60 = Count('pk', filter=Q(datetime__gte=date_60)),
    raid_90 = Count('pk', filter=Q(datetime__gte=date_90)),
    raid_life = Count('pk'),
)

Character.objects.annotate(
    raid_30 = Count('raids', filter=Q(raids__datetime__gte=date_30)),
    raid_60 = Count('raids', filter=Q(raids__datetime__gte=date_60)),
    raid_90 = Count('raids', filter=Q(raids__datetime__gte=date_90)),
    raid_life = Count('raids')
).annotate(
    raid_30_percent = F('raid_30')/raids_count['raid_30'],
    raid_60_percent = F('raid_60')/raids_count['raid_60'],
    raid_90_percent = F('raid_90')/raids_count['raid_90'],
    raid_life_percent = F('raid_life')/raids_count['raid_life'],
)