通过中间表添加多个关系时的完整性错误

Question

class Operation(models.Model):
    Operation_Name = models.CharField(max_length = 100)

class Doctor(models.Model):
    Name = models.CharField(max_length = 100)
    Related_Operations = models.ManyToManyField(Operation,through='Unique_Operation_Doctor_Patient_Relation')

    def __str__(self):
        return self.Name

class Unique_Operation_Doctor_Patient_Relation(models.Model):   
# the doctor and the operation
    Concerned_Doctor = models.ForeignKey(Doctor)
    Concerned_Operation = models.ForeignKey(Operation)

# Attributes of the operation
    Date = models.DateTimeField(db_index = True)
    Tooth_Surface = models.IntegerField(db_index = True)
    Amount = models.IntegerField(db_index = True)
    Concerned_Patient = models.ForeignKey(Patient,db_index = True)
    Idtag = models.AutoField(primary_key = True,default = 200000,db_index = True)

以下是两个模型Doctor和Operation之间通过中间模型建立的多对多关系。我还添加了一个外键字段，将其链接到患者，以便我可以访问患者记录。我为中间模型创建了一个表单。在这个模型中，我保存了医生和患者的关系，但我只在视图功能中添加了与患者的关系。

class Try_Form(forms.ModelForm):
    class Meta:
        model = Unique_Operation_Doctor_Patient_Relation
        fields = ['Concerned_Doctor','Concerned_Operation','Concerned_Patient','Date','Tooth_Surface','Amount',]


        help_texts ={
    'Date': '   (YYYY-MM-DD)', 
    }

    New_Operation_Name = forms.CharField(max_length = 100)
    New_Doctor_Name = forms.CharField(max_length = 100)

    field_order = ['Date','Tooth_Surface','Amount','Concerned_Operation','New_Operation_Name','Concerned_Doctor','New_Doctor_Name','Concerned_Patient']

    def __init__(self,*args,**kwargs):
        super(Try_Form,self).__init__(*args,**kwargs)
        self.fields['Concerned_Doctor'].required = False
        self.fields['Concerned_Operation'].required = False
        self.fields['Concerned_Patient'].required = False

    def clean(self):
        # The connected doctors. Creating new Doctors if they don't exist and connecting them. The same for operations. 
        Existing_Operation_Connection = self.cleaned_data.get('Concerned_Operation')
        New_Operation_Connection = self.cleaned_data.get('New_Operation_Name')

        if Existing_Operation_Connection and not New_Operation_Connection:
            self.Concerned_Operation = Existing_Operation_Connection
        elif not Existing_Operation_Connection and New_Operation_Connection:
            Possible_New_Operation,create = Operation.objects.get_or_create(Operation_Name = New_Operation_Connection)  
            if not create:
                self.Concerned_Operation = Possible_New_Operation
            else:
                self.Concerned_Operation = Possible_New_Operation
        else:
            raise ValidationError("Please do not add a new operation and select an existing operation in the same form.")

        Existing_Doctor_Connection = self.cleaned_data.get('Concerned_Doctor')
        New_Doctor_Connection = self.cleaned_data.get('New_Doctor_Name')

        if Existing_Doctor_Connection and not New_Doctor_Connection:
            self.Concerned_Doctor = Existing_Doctor_Connection
        elif not Existing_Doctor_Connection and New_Doctor_Connection:
            Possible_New_Doctor,create = Doctor.objects.get_or_create(Name = New_Doctor_Connection)
            if not create:
                self.Concerned_Doctor = Possible_New_Doctor
            else:
                self.Concerned_Doctor = Possible_New_Doctor
        else:
            raise ValidationError("Please do not add a new doctor and select an existing doctor in the same form.")

        return super(Try_Form,self).clean()

视图功能如下

    def patient_tryform(request, pk):
        if request.method == "POST":
            form = Try_Form(request.POST)
            if form.is_valid():
                new_operation = form.save(commit = False)
                connected_patient = Patient.objects.get(Patient_Id = pk)
                new_operation.Concerned_Patient = connected_patient
                new_operation.save()


                return redirect('patient_treatmentrecord',pk = pk)
        else:
            form = Try_Form()

return render(request,'patient/patient_addoperation.html',{'form':form})

我得到的错误是line =＆gt; new_operation.save（）

IntegrityError =＆gt; NOT NULL约束失败： patient_unique_operation_doctor_patient_relation.Concerned_Doctor_id。虽然我检查了python shell并且使用唯一的主键创建了医生。