Question

我是Django / Python的初级程序员，现在我正在寻找一种强大的方法来创建和更新我的模型。我希望这是一个非常普遍的问题。如何以正确的方式执行此操作的一些示例代码将非常感激。

我遇到的问题是我不确定在哪里放置save（）命令。现在我有多个地方放置了save（）方法。有时我必须多次点击各种视图上的保存按钮，然后才能在低级别上更改为更高级别的模型。

在本例中，我使用两个名为Medium和Circuit的简化模型。指定了两个模型的create方法以及set_medium和set_circuit方法，这显示了我当前是如何做的。

class Circuit(models.Model):
    medium              = models.ForeignKey('medium.Medium', related_name='medium_related', on_delete=models.CASCADE)
    temperature         = models.FloatField(default=60, help_text='[degC]')
    glycol_percentage   = models.FloatField(default=0, choices = choices.GLYCOL_PERCENTAGE)

    @classmethod
    def create( cls, 
                temperature,
                glycol_percentage):

        circuit = cls(  temperature         = temperature,
                        glycol_percentage   = glycol_percentage)

        circuit.medium = Medium.create(circuit.temperature, circuit.glycol_percentage)
        circuit = circuit.set_circuit(circuit)
        circuit.save()
        return circuit

    def set_circuit(self, circuit):
        circuit.medium.glycol_percentage    = circuit.glycol_percentage
        circuit.medium.temperature          = circuit.temperature
        circuit.medium                      = circuit.medium.set_medium(circuit.medium)
        return circuit

class Medium(models.Model):
    glycol_percentage       = models.FloatField(default=0, choices = choices.GLYCOL_PERCENTAGE)
    temperature             = models.FloatField(default=60, help_text='[degC]')

    # Calculated properties
    rho                     = models.FloatField(default=1000, help_text='[kg/m3]')

    @classmethod
    def create( cls, temperature, glycol_percentage):
        medium = cls(   temperature         = temperature, 
                        glycol_percentage   = glycol_percentage)
        medium = medium.set_medium(medium)
        medium.save()
        return medium

    def set_medium(self, medium):
        medium.rho                     = services.rho(temperature=medium.temperature, glycol_percentage=medium.glycol_percentage)
        return medium

以下是我通常编写“创建和更新”视图的方法。

class CircuitCreateView(LoginRequiredMixin, CreateView):
    model = Circuit
    template_name = 'circuit/create.html'
    form_class = CircuitForm

    def form_valid(self, form):
        circuit = Circuit.create(   glycol_percentage   = form.cleaned_data['glycol_percentage'],
                                    temperature         = form.cleaned_data['temperature'])
        circuit.save()
        return HttpResponseRedirect(reverse('circuit:detail', args=(circuit.id,)))    

class CircuitUpdateView(LoginRequiredMixin, UpdateView):
    model = Circuit
    template_name = 'circuit/detail-update.html'
    form_class = CircuitForm

    def form_valid(self, form):
        circuit = get_object_or_404(Circuit, pk=self.kwargs['pk_circuit'])
        circuit.glycol_percentage   = form.cleaned_data['glycol_percentage']
        circuit.temperature         = form.cleaned_data['temperature']
        circuit                     = circuit.set_circuit(circuit)
        circuit.save()
        return HttpResponseRedirect(reverse('circuit:detail', args=(circuit.id,)))

Django多模型更新/创建

0 个答案: