Question

For the following models:

class Price:
    cad = models.DecimalField(max_digits=8, decimal_places=2)
    usd = models.DecimalField(max_digits=8, decimal_places=2)

class Product:
    name = models.CharField(max_length=255)
    price = models.ForeignKey(Price)

For each product, it’s related to one and only one Price object which will contain either a Canadian or US dollar value. Is the above the proper way of doing setting that relationship? Here are some sample data:

Shirt, $100 US, $120 CAD
Book, $20 US, $25 CAD

I also want to input the above information from the admin so that interface will be similar to the following:

Add a Product:

• name:
• CAD:
• USD:

I can more or less do the above with the following code:

class ProductInline(admin.StackedInline):
    model = Product

class PriceAdmin(admin.ModelAdmin):
    inlines = [
        ProductInline,
    ]

Am I doing it the proper way?

Answer 1

I think you have to use one2one relationships

class Price:
    cad = models.DecimalField(max_digits=8, decimal_places=2)
    usd = models.DecimalField(max_digits=8, decimal_places=2)

class Product:
    name = models.CharField(max_length=255)
    price = models. OneToOneField(Price, primary_key=True)

http://www.djangoproject.com/documentation/models/one_to_one/