Adjusting current code to be able to add items from new table to the basket

Question

My website is currently adapted to deal with things like adding to the cart, removing from the cart and creating an order, only on one Item table. I wanted to add different products to the site, so I need to create a new table, that will handle other items. The thing is, that I am not really sure how to properly implement that to my website, so things like adding to the cart and creating order would work with that new table as well.

So thats the model of the first Item table:

class Item(models.Model):
  title = models.CharField(max_length=100)
  price = models.FloatField()
  discount_price = models.FloatField(blank=True, null=True)
  category = models.ManyToManyField(Category)
  label = models.CharField(choices=LABEL_CHOICES, max_length=1)
  slug = models.SlugField()
  description = models.TextField()
  image = models.ImageField()

  def __str__(self):
      return self.title

  def get_absolute_url(self):
      return reverse("core:product", kwargs={
          'slug': self.slug
      })

  def get_add_to_cart_url(self):
      return reverse("core:add-to-cart", kwargs={
          'slug': self.slug
      })

  def get_remove_from_cart_url(self):
      return reverse("core:remove-from-cart", kwargs={
          'slug': self.slug
      })

When you add item to the cart it goes to this table:

class OrderItem(models.Model):
  user = models.ForeignKey(settings.AUTH_USER_MODEL,
                         on_delete=models.CASCADE)
  ordered = models.BooleanField(default=False)
  item = models.ForeignKey(Item, on_delete=models.CASCADE)
  quantity = models.IntegerField(default=1)

Can I just add a new foreign key to this table and everything would work as it should? How to deal with things like adding product from just one table? The field for the other would be blank then?

order model:

class Order(models.Model):
  user = models.ForeignKey(settings.AUTH_USER_MODEL,
                         on_delete=models.CASCADE)
  ref_code = models.CharField(max_length=20, blank=True, null=True)
  items = models.ManyToManyField(OrderItem)
  start_date = models.DateTimeField(auto_now_add=True)
  ordered_date = models.DateTimeField()
  ordered = models.BooleanField(default=False)
  shipping_address = models.ForeignKey(
      'Address', related_name='shipping_address', on_delete=models.SET_NULL, blank=True, null=True)

and finally the new table, that will store other items:

class Accessory(models.Model):
  title = models.CharField(max_length=100)
  price = models.FloatField()
  discount_price = models.FloatField(blank=True, null=True)
  category = models.ManyToManyField(Category)
  label = models.CharField(choices=LABEL_CHOICES, max_length=1)
  slug = models.SlugField()
  description = models.TextField()
  image = models.ImageField()

Anyone can help me get this to work with that new table called Accessory?

Answer 1

Looking at your Item and Accessory model definitions, those two look very similar. My recommendation would be to create a OneToOne relationship between Accessory and Item tables, so you would not need to deal with this redundancy.

If you do it like this, all the functionalities related to Item table would be inherited by the Accessory table as well. I think it will reduce costs and overheads of changing your logic.

class Accessory(models.Model):
    item = models.OneToOneField(Item, on_delete=models.CASCADE)
    ...
    # other fields that will differ between Accessory and Item

You can even use the connected Item record as your Accessory model's primary_key .