django rest framework get()返回了多个对象,尽管使用了filter()方法
在django rest framework get()返回了多个对象,尽管使用了filter()方法,django,django-rest-framework,Django,Django Rest Framework,在model.py中,我有两个模型 class student(models.Model): name = models.CharField(max_length=255) registration_number = models.CharField(max_length=255) session = models.CharField(max_length=255) college = models.ForeignKey(to='college', on_dele
model.py
中,我有两个模型
class student(models.Model):
name = models.CharField(max_length=255)
registration_number = models.CharField(max_length=255)
session = models.CharField(max_length=255)
college = models.ForeignKey(to='college', on_delete=models.CASCADE)
class Meta:
db_table = 'student'
class semester(models.Model):
semester = models.IntegerField()
student = models.ForeignKey(to='student', on_delete=models.CASCADE)
sgpa = models.FloatField()
grade = models.CharField(max_length=255)
is_fail = models.BooleanField(default=True)
class Meta:
db_table = 'semester'
序列化程序类看起来像
class SemesterSerializer(serializers.ModelSerializer):
class Meta:
model = models.semester
fields = ('id', 'semester', 'sgpa', 'grade', 'is_fail',)
class StudentSerializer(serializers.ModelSerializer):
class Meta:
model = models.student
fields = ('id', 'name', 'registration_number', 'college', 'session',)
和views.py
包含
class SemesterViewSet(viewsets.ModelViewSet):
def get_queryset(self):
if 'semester' in self.kwargs:
return models.semester.objects.filter(semester=self.kwargs['semester'])
else:
return models.semester.objects.all()
lookup_field = 'semester'
serializer_class = serializer.SemesterSerializer
url模式是
router = DefaultRouter()
router.register('semester', views.SemesterViewSet, base_name='semester')
urlpatterns = [
url(r'', include(router.urls)),
]
当我试图访问
url/sement/8
时,multipleobjects返回了exception,并显示get()返回了一个以上的学期——它返回了2代码>错误消息。这里我没有使用任何get()
方法。为什么会发生这种情况,解决方案是什么?我需要显示学期的所有结果。从视图中删除lookup\u字段
,或将其更改为lookup\u字段='id'
错误是因为在调用retrieve()
方法时,该方法内部调用了一个与查询类似的get\u object()
示例:
semester.objects.get(semester=8)
因此,如果有超过1个学期实例具有相同的学期
值,则会引发错误
更新-1
尝试覆盖视图中的retrieve()
方法,
from rest_framework.response import Response
class SemesterViewSet(ModelViewSet):
def get_queryset(self):
if 'semester' in self.kwargs:
return semester.objects.filter(semester=self.kwargs['semester'])
else:
return semester.objects.all()
lookup_field = 'semester'
serializer_class = SemesterSerializer
def retrieve(self, request, *args, **kwargs): # Change is here <<
serializer = self.get_serializer(self.get_queryset(), many=True)
return Response(data=serializer.data)
来自rest\u framework.response导入响应
类SemesterViewSet(ModelViewSet):
def get_queryset(自我):
如果self.kwargs中的“学期”:
return sement.objects.filter(sement=self.kwargs['sement'])
其他:
return.objects.all()
查找_字段='学期'
serializer_class=semestSerializer
def retrieve(self,request,*args,**kwargs):#这里是Changeself.kwargs['sement']
需要sement
,所以我不能删除lookup_字段,因为sement
所以,您试图根据sement
值检索所有实例?
semester.objects.get(semester=8)
from rest_framework.response import Response
class SemesterViewSet(ModelViewSet):
def get_queryset(self):
if 'semester' in self.kwargs:
return semester.objects.filter(semester=self.kwargs['semester'])
else:
return semester.objects.all()
lookup_field = 'semester'
serializer_class = SemesterSerializer
def retrieve(self, request, *args, **kwargs): # Change is here <<
serializer = self.get_serializer(self.get_queryset(), many=True)
return Response(data=serializer.data)