如何将模型的实例传递给 Django 中的另一个模型？

Question

I'm trying to populate dbkey column from parent table on the form, where foreign table values are input. WHile providing a value I get the following error - "csg_ch_servers.DBParentCustomerKey" must be a "csg_ch_customer" instance. Could someone help me out?

model.py

class csg_ch_customer(models.Model):
    DBKey=models.AutoField(primary_key=True)
    CustomerName=models.CharField(max_length=100,unique=True)
    class Meta:
        db_table="csg_ch_customer"
    def  __unicode__(self):
        return self.DBKey
    def __init__(self):
        return self.DBKey

class csg_ch_servers(models.Model):
    DBKey=models.AutoField(primary_key=True)
    DBParentCustomerKey=models.ForeignKey(csg_ch_customer,on_delete=models.CASCADE)
    class Meta:
        db_table="csg_ch_servers"
    def __str__(self):
        return self.DBParentCustomerKey
    def __unicode__(self):
        return self.DBParentCustomerKey

form.py

class csg_ch_customer_form(forms.ModelForm):

    class Meta:
        model  = models.csg_ch_customer
        fields = "__all__"

class csg_ch_servers_form(forms.ModelForm):

    class Meta:
        model  = models.csg_ch_servers
        fields = "__all__"

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.fields['DBParentCustomerKey'].queryset = models.csg_ch_customer.objects.values_list('DBKey', flat=True)

views.py

def register_ser(request):
    form=Aforms.csg_ch_servers_form()
    if request.method == "POST":
        form=Aforms.csg_ch_servers_form(request.POST)
        if form.is_valid():
            form.save()
            return redirect('Admin/NewServer.html')
    else:
        return render(request,'Admin/NewServer.html',{'form':form})
    return render(request,'Admin/NewServer.html',{'form':form})

Answer 1

Your form needs to instanciate your model in your views. I added few fields to your view, but you need to edit it for your own purpose.

This should be as simple as possible.

def register_ser(request,pk):
    yourmodel = models.csg_ch_customer.objects.get(pk=pk)
    form=Aforms.csg_ch_servers_form(instance=yourmodel)
    if request.method == "POST":
        form=Aforms.csg_ch_servers_form(request.POST,instance=yourmodel)
        if form.is_valid():
            form.save()
            return redirect('Admin/NewServer.html')
    else:
        return render(request,'Admin/NewServer.html',{'form':form})
    return render(request,'Admin/NewServer.html',{'form':form})