Django: Data uownership for users - django

Question

I am trying to create a simple app. It has the following model:
Model: Product
class Product(models.Model):
product_owner = models.ForeignKey(User, verbose_name='User')
product_title = models.CharField(max_length=100, null=False,
verbose_name='Product title')
product_description = models.TextField(max_length=250, verbose_name='Product description')
product_qty = models.IntegerField(verbose_name='Quantity')
product_mrp = models.DecimalField(max_digits=12, decimal_places=2, verbose_name='Maximum retail price')
product_sku = models.CharField(max_length=100, null=False, unique=True, verbose_name='SKU',help_text='Enter Product Stock Keeping Unit')
product_barcode = models.CharField(max_length=100, null=False, verbose_name='Barcode')
I am using only the built in Admin App provided by django framework. And I was able to Make the Product data availaible for only the respective user by adding the following in the Admin classes.
class ProductAdmin(ImportExportModelAdmin):
exclude = ('product_owner',)
list_display = ['product_title','product_description', 'product_qty',
'product_mrp','product_sku','product_barcode']
search_fields = ['product_title', 'product_description', 'product_sku',
'product_barcode']
ordering = ['id']
list_display_links = ['product_title']
def get_queryset(self, request):
if request.user.is_superuser:
return Product.objects.all()
return Product.objects.filter(product_owner=request.user)
def save_model(self, request, obj, form, change):
if not change:
obj.product_owner = request.user
obj.save()
As I just started experimenting, I added 2 users, User1 and User2.
For User1 I added 10 products. Then I loggen in as User2 and User2 cannot see the products added by User1.
Now when I am tying to add products for User2, and if there is a conflict in product_sku field which is a unique field, I cannot add the product at all.
How to solve this. I need each user to add his own products, but product_sku unique to his set of products data, not for the whole database.

Answer 1

Instead of defining unique=True on the product_sku field, you should define unique_together for sku and user.
class Product(models.Model):
...
class Meta:
unique_together = (('product_sku', 'product_owner'),)
This will ensure that each user can only have one product with a particular sku, but multiple users can have the same sku.