如何修复django模型实例

Question

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

当我试图创建一个新的卡片或诊断时，我会得到上面的错误。卡片和诊断应该是病人的一个实例，就像病人有卡片和诊断一样。病人类有一个引用用户的预键。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，您不能将其保存到API或保存到模型中。为了清楚起见，它不是Patient对象。

根据您的情况，我将将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User()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)

备注：

1. ，这是一个单向引用的解决方案.( Patient)
2. If被称为User，您在User和Patience之间有交叉引用关系(其中用户和耐心之间有一个ForeignKey )，然后声明您的User模型。
3. 解决方案从用户询问病人。因为用户与该外部对象不兼容.