事务

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correction = Correction.objects.get(id=self.kwargs.get('pk'))
correction.correct_at = timezone.now()
correction.correct_user_id = self.request.user.id
with transaction.atomic():
    correction.save()
    Inbox.objects.new_notify(
        user_id=correction.report_user.id,
        title=f"#{self.kwargs.get('pk')} 纠错已处理",
        content=f"<p>您的错误反馈 #{self.kwargs.get('pk')} 已处理 </p>"
                f"<p>点击<a href='/tk/question/{correction.question.id}'>这里</a>查看对应的题目</p>",
        extra_type=Inbox.EXTRA_PLATFORM
    )
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qs.values('a')
QS<{a:b},{a:c} >


qs.values_list('a')
QS<(b,), (c,)>


qs.values_list('a', flat=True)
QS<[b, c]>
# flat=True只能在只要看一个参数的时候使用
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def get_queryset(self):
    _filter = self.request.GET.get('filter', 'dashboard')
    if _filter == 'dashboard':
        qs = School.objects.filter(is_active=True).exclude(id__in=settings.DASHBOARD_EXCLUDE_SITES)
        if site_ids := settings.STATIS_USER_SITE.get(self.request.user.id):
            qs = qs.filter(id__in=site_ids)
    else:
        qs = School.objects.filter(is_active=True).order_by('site_title')
    return qs

上面的代码本来不会出问题的。

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def get_queryset(self):
    _filter = self.request.GET.get('filter', 'dashboard')
    user_id = self.request.user.id
    if _filter == 'dashboard':
        if self.request.user.username == 'fljy':
            qs = School.objects.filter(is_active=True).exclude(
                id__in=settings.DASHBOARD_EXCLUDE_SITES
            )
        else:
            qs = OperatorSchool.objects.filter(
                user_id=user_id,
                school__is_active=True
            )
    else:
        qs = School.objects.filter(is_active=True).order_by('site_title')
    return qs

结果因为加了一个用户只能查看他所管理的学校之后，就出bug了，我发现原因是qs不在是School模型的queryset，而是变成OperatorSchool了。

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class OperatorSchool(BaseModel):
    """
    后台管理: 运营管理的学校
    since: 21.6.16
    """
    user = models.ForeignKey(User, verbose_name='运营', db_index=False, on_delete=CASCADE)
    school = models.ForeignKey('market.School', verbose_name='负责学校', db_index=False, on_delete=CASCADE)

    class Meta:
        unique_together = (('user', 'school'),)

以上是他的模型定义。我应该如何将else分支里的内容转化为School？

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school_ids = OperatorSchool.objects.filter(
    user_id=user_id,
    school__is_active=True
).values_list('school_id', flat=True)
qs = School.objects.filter(id__in=school_ids)

进一步优化成一个语句

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qs = School.objects.filter(
    operatorschool__user_id=user_id,
    operatorschool__school__is_active=True
).distinct()

双杠优化

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# 如果这个卷子被班级练过很多次，就取班级练的最好的一次得分率
# max_percent = PaperClassQuestionPercent.objects.filter(
#     paper_question=PaperQuestion.objects.get(
#         paper=task_obj.paper,
#         question_id=question.question_id
#     )
# ).order_by('-correct_percent').first().correct_percent

# 如果这个卷子被班级练过很多次，就取班级练的最好的一次得分率
max_percent = PaperClassQuestionPercent.objects.filter(
    paper_question__paper=task_obj.paper,
    paper_question__question_id=question.question_id
).order_by('-correct_percent').first().correct_percent

python代码尽量不要写函数嵌套，否则影响性能