如何修复 django 模型实例

Question

错误消息 ValueError：无法分配“”：“Diagnoses.owner”必须是“Patient”实例

当我尝试创建新卡或诊断时出现上述错误。 卡片和诊断是患者的一个实例，就像患者拥有卡片和诊断一样。患者类有一个引用用户的外键。 这是代码

views.py

    from django.shortcuts import render
from rest_framework.generics import ListCreateAPIView, RetrieveUpdateDestroyAPIView
from .serializers import PatientsSerializer, PatientsCardSerializer, PatientsDiagnosesSerializer
from .models import Patient, Card, Diagnoses
from rest_framework import permissions
from .permissions import IsOwner


# Patient Views
class PatientListAPIView(ListCreateAPIView):
    serializer_class = PatientsSerializer
    queryset = Patient.objects.all()
    permission_classes = (permissions.IsAuthenticated, IsOwner,) 
    def perform_create(self, serializer):
        return serializer.save(owner=self.request.user)
    def get_queryset(self):
        return self.queryset.filter(owner=self.request.user)

class PatientDetailAPIView(RetrieveUpdateDestroyAPIView):
    serializer_class = PatientsSerializer
    permission_classes = (permissions.IsAuthenticated, IsOwner,)
    queryset = Patient.objects.all()
    lookup_field = "id"
    def get_queryset(self):
        return self.queryset.filter(owner=self.request.user)


class PatientCardListAPIView(ListCreateAPIView):
    serializer_class = PatientsCardSerializer
    queryset = Card.objects.all()
    permission_classes = (permissions.IsAuthenticated,) 
    def perform_create(self, serializer):
        return serializer.save(owner=self.request.user)
    def get_queryset(self):
        return self.queryset.filter(owner=self.request.user)

class PatientCardDetailAPIView(RetrieveUpdateDestroyAPIView):
    serializer_class = PatientsCardSerializer
    permission_classes = (permissions.IsAuthenticated, IsOwner,)
    queryset = Card.objects.all()
    lookup_field = "id"
    def get_queryset(self):
        return self.queryset.filter(owner=self.request.user)



class PatientDiagnosesListAPIView(ListCreateAPIView):
    serializer_class = PatientsDiagnosesSerializer
    queryset = Diagnoses.objects.all()
    permission_classes = (permissions.IsAuthenticated,) 
    def perform_create(self, serializer):
        return serializer.save(owner=self.request.user)
    def get_queryset(self):
        return self.queryset.filter(owner=self.request.user)

class PatientDiagnosesDetailAPIView(RetrieveUpdateDestroyAPIView):
    serializer_class = PatientsDiagnosesSerializer
    permission_classes = (permissions.IsAuthenticated, IsOwner,)
    queryset = Diagnoses.objects.all()
    lookup_field = "id"
    def get_queryset(self):
        return self.queryset.filter(owner=self.request.user)

Models.py

class Patient(models.Model):
    name = models.CharField(max_length=255, null=True)
    country = models.CharField(max_length=255, null=True)
    state = models.CharField(max_length=255, null=True)
    phone = models.CharField(max_length=255, null=True)
    email = models.CharField(max_length=255, null=True)
    owner = models.ForeignKey(to=User, null=True, on_delete=models.CASCADE)
    def __str__(self):
        return self.name
class Card(models.Model):    
    name = models.CharField(max_length=255, null=True)
    card_number = models.CharField(max_length=255, null=True)    
    owner = models.OneToOneField(Patient, null=True, blank=True, on_delete=models.CASCADE)
    def __str__(self):
        return (self.patient.name)+"'s card"
   
class Diagnoses(models.Model):
    sickness = models.CharField(max_length=255, null=True)
    note = models.TextField(max_length=255, null=True)   
    owner = models.ForeignKey(Patient, null=True, on_delete=models.SET_NULL)
    def __str__(self):
        return (self.patient.name)+"'s diagnoses"

Answer 1

到目前为止，self.request.user 是一个 User 对象。因此，您无法将其保存到 API 或模型中。为了清楚起见，它不是 Patient 对象。

根据您的情况，我会将Patient 对象与User 对象（如果这是单向引用对象）排队，并将其放入参数中并执行 save() 方法。

class PatientCardListAPIView(ListCreateAPIView):
    serializer_class = PatientsCardSerializer
    queryset = Card.objects.all()
    permission_classes = (permissions.IsAuthenticated,) 

    def perform_create(self, serializer):
        getPatientFromUser = Patient.objects.get(owner=self.request.user)
        # getPatientFromUser returns `Patient` Instance. So you could bind it in `Card` Model.
        return serializer.save(owner=getPatientFromUser)

    def get_queryset(self):
        return self.queryset.filter(owner=self.request.user)

注意事项：

1. 这是一种单向参考解决方案。 （User 被称为Patient）
2. 如果您在 User 和 Patience 之间存在交叉引用关系（其中 User 和 Patience 之间有一个 ForeignKey），则声明您的 User 模型。
3. 解决方案向用户查询患者。由于用户与该外部对象不兼容。