过滤的嵌套关系 Django Rest 框架

Question

我有两个模型，如下所示：

class Subject(models.Model):

   subject_code = models.CharField(max_length=12, unique=True)
   name = models.CharField(max_length=100)
   dept_code = models.CharField(max_length=6)

还有……

class Subject_assessment(models.Model):    
   subject_code = models.ForeignKey(Subject, related_name='sub_assessments')
   year = models.CharField(max_length=4)
   name = models.CharField(max_length=50)

我以这样的方式创建了我的序列化，当我检索一个主题时，我也会检索与该主题相关的评估。我正在使用以下序列化程序来完成此操作：

class AssessmentsSerializer(serializers.ModelSerializer):
class Meta:
    model = Subject_assessment
    fields = (
        "subject_code", "year", "name"
    )

class SubjectSerializer(serializers.ModelSerializer):
sub_assessments = AssessmentsSerializer(many=True)
class Meta:
    model = Subject
    fields = (
        "subject_code", "name", "dept_code",            
        "sub_assessments"
    )

这段代码可以完美运行，因为它给了我这样的结果：

{
 "subject_code":"ECR2243",
 "name":"Statistics",
 "dept_code":"Stats",
 "sub_assessments":[
     {
       "subject_code":"ECR2243",
       "year":"2017",
       "name":"Test 1"
     },
     {
       "subject_code":"ECR2243",
       "year":"2016",
       "name":"Test 1"
     }
 ]
}

我的问题是我只想检索特定年份的评估。例如，如果我通过 2017 作为感兴趣的年份，我不希望像现在这样检索 2016 的评估。

任何人都可以帮助我如何构建我的代码以完成此任务。提前谢谢你。

---

编辑 1 我的views.py如下：

class  SubjectViewSet(viewsets.ModelViewSet):
serializer_class = SubjectSerializer
lookup_field = 'subject_code'

def get_queryset(self):
    qry_subject_code = self.request.GET.get('subject_code')
    retrieved_sub = Subject.objects.filter(subject_code=qry_subject_code)
    return retrieved_sub

Answer 1

这是对我有用的解决方案：

class FilteredAssessmentsSerializer(serializers.ListSerializer):
    def to_representation(self,data):
       qry_year = self.context['request'].GET.get('year')
       data = data.filter(year=qry_year)
       return super(FilteredAssessmentsSerializer,  self).to_representation(data)

class AssessmentsSerializer(serializers.ModelSerializer):
   class Meta:
      model = Subject_assessment
      list_serializer_class = FilteredAssessmentsSerializer
      fields = '__all__'

class SubjectSerializer(serializers.ModelSerializer):
   sub_assessments = AssessmentsSerializer(many=True)
   class Meta:
       model = Subject
       fields = (
          "subject_code", "name", "dept_code",
          "faculty_code", "university_code", "description",
          "sub_assessments"
       )

参考：我结合了以下解决方案，想出了一个适合我的解决方案。

How can I apply a filter to a nested resource in Django REST framework?

https://stackoverflow.com/a/28354281/7210105

Answer 2

你能试试这个查询吗：

retrieved_sub = Subject_assessment.objects.filter(subject_code__in=Subject.objects.filter(subject_code=qry_subject_code),year='2014').all()