Python Django将外键传递给视图

嗨，也许有人能给我指出正确的方向，我正在通过与Django的探戈学习Django，我也在跟随官方的Django教程，并为采购订单创建我自己的Django应用程序

我需要了解如何访问另一个模型的外键详细信息并使用表单保存它。基本上，我的应用程序有订单和供应商。创建订单时，我可以让供应商外键选项显示在表单上，但当我保存它时，我还想将供应商名称保存到订单表中，当前它只保存供应商id，我已经搜索了很多不同场景的例子，但就是不明白，谢谢

view.py

def add_order(request):
    if request.method == 'POST':
        form = OrderForm(request.POST)
        if form.is_valid():
            form.save(commit=True)
            return orders(request)
        else:
            print(form.errors)
    else:
        form = OrderForm()

    context_dict = {'form':form}

    return render(
        request,
        'purchaseorders/add_order.html',
        context_dict
    )

model.py

# Create your models here.

class Supplier(models.Model):
    supplier_code = models.CharField(max_length=10)
    supplier_name = models.CharField(
        max_length=100,
        unique=True
    )
    supplier_email = models.EmailField(max_length=100)
    supplier_website = models.URLField(max_length=100)
    slug = models.SlugField(unique=True)

    def save(self, *args, **kwargs):
        self.slug = slugify(self.supplier_name)
        super(Supplier,self).save(*args, **kwargs)

    def __unicode__(self):
        return self.supplier_name

    def __str__(self):
        return self.supplier_name

    class Meta:
        verbose_name_plural = "Suppliers"


class Order(models.Model):
    supplier = models.ForeignKey(Supplier)
    po_number = models.IntegerField(default=0)
    ordered_by = models.CharField(max_length=50)
    order_date = models.DateTimeField()
    supplier_name = models.CharField(max_length=50)
    net_value = models.DecimalField(
        decimal_places=2,
        max_digits=10
    )

    class Meta:
        verbose_name_plural = "Orders"

    def __unicode__(self):
        return self.po_number

forms.py

from django import forms
from PurchaseOrders.models import Supplier, Order

class SupplierForm(forms.ModelForm):
    supplier_code = forms.CharField(
        max_length=10,
        help_text="Please enter a unique code"
    )
    supplier_name = forms.CharField(
        max_length=100,
        help_text="Please enter the Suppliers full name"
    )
    supplier_email = forms.EmailField(
        max_length=100,
        help_text="Please enter a email address"
    )
    supplier_website = forms.URLField(
        max_length=100,
        help_text="Please enter a website"
    )
    slug = forms.CharField(
        widget=forms.HiddenInput(),
        required=False
    )

# an inline class to provide additional information on the form
    class Meta:
        # provide an association between the ModelForm and model
        model = Supplier
        fields = (
            'supplier_code', 'supplier_name', 
            'supplier_email', 'supplier_website'
        )

class OrderForm(forms.ModelForm):
    #list all form details except the Foreignkey connection
    po_number = forms.IntegerField(
        help_text="please enter a PO Number"
    )
    ordered_by = forms.CharField(
        max_length=50,
        help_text="please enter your name"
    )
    order_date = forms.DateTimeField(
        help_text="please enter a date of order"
    )
    #supplier_name = forms.ModelChoiceField(
        queryset=Supplier.objects.all()
    )
    net_value = forms.DecimalField(
        decimal_places=2,
        max_digits=10,
        help_text="please enter a net amount"
    )

    class Meta:
        # provide an association between the ModelForm and model
        model = Order

html

---

从问题开始，您可以在模型的保存方法中捕获此数据：

class Order(models.Model):
    [...]
    def save(self, *args, **kw):
        if self.supplier_id is not None:
            self.supplier_name = self.supplier.supplier_name
        super(Order, self).save(*args, **kw)

然而，尽管在某些情况下上述内容可能是正确的，例如如果供应商名称预计会发生变化，但更典型的情况是通过现有关系访问相关字段，例如：

myorder.supplier.supplier_name

---

你为什么要这么做？这是不必要的重复数据。订单始终可以通过外键访问供应商名称，因此，保存该名称的单独副本是没有意义的。有效的一点是，我想我只是想了解如果我想这样做，我可以怎么做，然后就像你指出的那样，我意识到没有必要。我的另一个想法是，如果我使用供应商模型中的另一个字段，我如何根据该字段找到id，然后保存它，当我尝试这样做时，我会在foreignkey上得到完整性空约束错误，谢谢，我现在在模板中得到了myorder.supplier.supplier\u名称显示，我知道这是更好的答案。

myorder.supplier.supplier_name