django orm 使用关联字段查询和更新

关联字段查询

_exam_fields = ['add_datetime', 'times', 'start_date', 'end_date', 'uuid', 'name', 'img', 'duration',
                         'bx_duration']
         _alias_fields = {
             'pass_score': F('score'), 'exam_paper_id': F('exam_paper__uuid'),
             'exam_paper_name': F('exam_paper__name'),
             'again_uuid': Value('', output_field=CharField())
         }
         _exam__filter = {'exam_range__org__org_user__user_id': self.request.user_id}
         query_exam = Exam.objects.filter(**_exam__filter).values(*_exam_fields).annotate(**_alias_fields).order_by(
             '-add_datetime')

         _again_fields = ['add_datetime', 'times', 'start_date', 'end_date', ]
         _alias_fields = {
             'uuid': Value('', output_field=CharField()), 'name': F('exam__name'), 'img': F('exam__img'),
            'duration': F('exam__duration'), 'bx_duration': F('exam__bx_duration'), 'pass_score': F('exam__score'),
             'exam_paper_id': F('exam__exam_paper__uuid'), 'exam_paper_name': F('exam__exam_paper__name'),
            'again_uuid': F('uuid'),
         }

使用关联字段更新

 UserCert.objects.filter(
        exam_record__is_pass=True,
        status=1
    ).update(
        user=Subquery(
            ExamRecord.objects.filter(
                uuid=OuterRef('exam_record_id'),
                is_pass=True
            ).values('user')[:1]
        ),
        status=2
    )

使用子查询过滤

subquery = MockExamRecord.objects.filter(
            mock_exam_id=OuterRef('mock_exam_id'),
            user_id=self.request.user_id,
        ).order_by('-add_datetime').values('add_datetime')[:1]

        obj_list = MockExamRecord.objects.filter(
            add_datetime__in=Subquery(subquery),
            user_id=self.request.user_id,
        ).distinct('mock_exam_id')