Django for循环保存实例

Question

我有一个表单，它有两个输入字段，它们返回必须解析的id值并将其添加到数据库中。

这是代码

        if form_stage_1.is_valid() and form_stage_2.is_valid():
        # GET the new TP to pass to the next instance

        form_stage_1.instance.created_by = self.request.user
        new_tp = form_stage_1.save()


        # Parse and add suppliers to the TP
        for supplier_id in request.POST["supplier"]:
            form_stage_2.instance.counterpart = Counterpart.objects.get(pk=supplier_id)
            form_stage_2.instance.side = 1
            form_stage_2.instance.save()
            form_stage_2.instance.transaction_proposal.add(new_tp)


        # Parse and add clients to the TP
        for client_id in request.POST["client"]:
            form_stage_2.instance.counterpart = Counterpart.objects.get(pk=client_id)
            form_stage_2.instance.side = 2
            form_stage_2.instance.save()
            form_stage_2.instance.transaction_proposal.add(new_tp)

        messages.success(request, "TP created successfully".format())
        return redirect("add-tp")

不幸的是，只添加了一个客户端..为什么form_stage_2.instance.save()只工作一次？

最合适的方法是什么？

Answer 1

首先，你有两张表格要填吗？

不管怎样，

for supplier_id in request.POST["supplier"]:
            form_stage_2.instance.counterpart = Counterpart.objects.get(pk=supplier_id)
            form_stage_2.instance.side = 1
            form_stage_2.instance.save()
            form_stage_2.instance.transaction_proposal.add(new_tp)

这行不通的。我相信你不能多次保存一个表单实例。

if form_stage_1.is_valid() and form_stage_2.is_valid():
    form_stage_1.instance.created_by = self.request.user
    new_tp = form_stage_1.save()

    # Parse and add suppliers to the TP
    for supplier_id in request.POST["supplier"]:
        data = {
            'counterpart':Counterpart.objects.get(pk=supplier_id),
            'side':1
            'transaction_proposal':[new_tp]
        }
        stage2_instance = Stage2ModelClass.objects.create(**data)


    # Parse and add clients to the TP
    for client_id in request.POST["client"]:
        data = {
            'counterpart':Counterpart.objects.get(pk=client_id),
            'side':2
            'transaction_proposal':[new_tp]
        }
        stage2_instance = Stage2ModelClass.objects.create(**data)

    messages.success(request, "TP created successfully".format())
    return redirect("add-tp")

解决方案可以是这样的。你可以使用，

    for client_id in request.POST["client"]:
        data = {
            'counterpart':Counterpart.objects.get(pk=client_id),
            'side':2,
            'transaction_proposal':[new_tp]
        }
        form = FormClassStage2(data)
        if form.is_valid():
            form.save()

但是我不认为你需要在这里初始化一个表单。