当我们有不同的类别和产品时，在 django 中设计模式的最佳方法

Question

我正在为一个电子商务市场网站设计 django 模型，用户可以在该网站上购买 4 种类型的产品。就像我有 4 种类型的差异模型一样。

衣服

class Merchandise(models.Model):
    adOwner = models.ForeignKey(VendorProfile, on_delete=models.CASCADE)
    imagesMerchandise = models.ManyToManyField(merchandiseImages)
    productName = models.CharField(max_length=50, null=False, blank=False)
    price = models.IntegerField()
    availableQuality=models.IntegerField()
    color=models.CharField(max_length=20, null=False, blank=False)
    size = models.CharField(max_length=50 , null=False , blank=False)
    description=models.CharField(max_length=250 , null=False , blank=False)
    is_approved = models.BooleanField(default=False)
    def __str__(self):
        return str(self.productName)

租车

class Vehicle(models.Model):
    adOwner=models.ForeignKey(VendorProfile, on_delete=models.CASCADE)
    carImages=models.ManyToManyField(Image)
    make=models.CharField(max_length=50, null=False, blank=False)
    modelName=models.CharField(max_length=50, null=False, blank=False)
    registrationNumber=models.CharField(max_length=50, null=False, blank=False)
    modelYear=models.CharField(max_length=50, null=False, blank=False)
    modelColor=models.CharField(max_length=50, null=False, blank=False)
    carType=models.CharField(max_length=50, null=False, blank=False)
    fuelMileage=models.CharField(max_length=50, null=False, blank=False)
    SeatingCapacity=models.CharField(max_length=50, null=False, blank=False)
    vehicleCondition=models.CharField(max_length=50, null=False, blank=False)
    fuelType=models.CharField(max_length=50, null=False, blank=False)
    price=models.CharField(max_length=50, null=False, blank=False)
    description=models.CharField(max_length=500, null=True, blank=True)
    registerIn=models.CharField(max_length=500, null=True, blank=True)
    is_approved = models.BooleanField(default=False)

    def __str__(self):
        return str(self.modelName)

预订酒店

class Accommodation(models.Model):
    adOwner = models.ForeignKey(VendorProfile, on_delete=models.CASCADE)
    hotleImages = models.ManyToManyField(HotleImages)
    accommodationTitle=models.CharField(max_length=150)
    location = models.CharField(max_length=150)
    accommodationName = models.CharField(max_length=150)
    checkIn = models.TimeField()
    checkOut = models.TimeField()
    # accessibility = models.CharField(max_length=20, null=False, blank=False)
    address = models.CharField(max_length=150)
    pets = models.CharField(max_length=150)
    child = models.CharField(max_length=150)
    is_approved = models.BooleanField(default=False)

创建活动

class ActivityOrganizer(models.Model):
    adOwner = models.ForeignKey(VendorProfile, on_delete=models.CASCADE)
    activityImage = models.ManyToManyField(ActivityImage)
    activityName = models.CharField(max_length=50 , null=False, blank=False)
    activityId = models.CharField(max_length=20, null=False, blank=False)
    ageSuggestion = models.CharField(max_length=20, null=True, blank=True)
    duration = models.CharField(max_length=20, null=False, blank=False)
    openTime = models.TimeField()
    closeTime=models.TimeField()
    expiryDate = models.DateField()
    availableQty = models.IntegerField()
    price = models.IntegerField()
    needToBring = models.CharField(max_length=50 , null=True , blank=True)
    personsAllowOnOneTicket = models.IntegerField()
    location = models.CharField(max_length=50 , null=True , blank=False)
    specialNotes = models.CharField(max_length=250 ,null=True , blank=True)
    description = models.CharField(max_length=250 , null=True , blank=True)
    is_approved = models.BooleanField(default=False)

现在我做了一个这样的订单表

class Orders(models.Model):
    order_number = models.AutoField(primary_key=True)
    total_amount = models.DecimalField(max_digits=10, decimal_places=2)
    ordertime = models.DateTimeField(auto_now_add=True)
    user_note=models.CharField(max_length=150 , null=True, blank=True)
    address=models.CharField(max_length=150 , null=True, blank=True)
    order_status = models.CharField(choices=STATUS , max_length=50)
    payment_status=models.BooleanField(default=0)

现在我很困惑如何将所有这 4 个类别绑定到我的订单对象。如果它是单一类别的，我可以简单地使用订单模型创建一个外键。但是我如何绑定所有这些（因为用户可以选择 1,2,3,4 个类别）所以如果用户选择住宿和车辆类别产品，我如何在外键中保存 2 个类别为空。任何帮助将不胜感激。谢谢

Answer 1

如果您的产品数量很少（在您的情况下为 4 个），并且每个订单只能订购一个类型的商品，那么您可以简单地将它们添加到 Orders 具有可空字段的模型中

class Orders(models.Model):
    order_number = models.AutoField(primary_key=True)
    total_amount = models.DecimalField(max_digits=10, decimal_places=2)
    ordertime = models.DateTimeField(auto_now_add=True)
    user_note=models.CharField(max_length=150 , null=True, blank=True)
    address=models.CharField(max_length=150 , null=True, blank=True)
    order_status = models.CharField(choices=STATUS , max_length=50)
    payment_status=models.BooleanField(default=0)
    merchandise = models.ForeignKey(Merchandise, on_delete=models.CASCADE, null=True, blank=True)
    vehicle = models.ForeignKey(Vehicle, on_delete=models.CASCADE, null=True, blank=True)
    accommodation = models.ForeignKey(Accommodation, on_delete=models.CASCADE, null=True, blank=True)
    activity_organizer = models.ForeignKey(ActivityOrganizer, on_delete=models.CASCADE, null=True, blank=True)

要列出特定类别的所有订单，请排除给定字段中所有为空的订单。

Orders.objects.exclude(merchandise__isnull=True)

此外，如果仅订购了一个类别产品，则其余 3 个字段将为空，如果您想强制执行该业务逻辑，则可以通过创建信号来检查它。