How do I implement a common interface for Django related object sets?

Question

Here\'s the deal:

I got two db models, let\'s say ShoppingCart and Order. Following the DRY principle I\'d like to extract some common prop

Answer 1

You can set the related_name argument of a ForeignKey, so if you want to make minimal changes to your design, you could just have ShoppingCartItem and OrderItem set the same related_name on their ForeignKeys to ShoppingCart and Order, respectively (something like "item_set"):

order = models.ForeignKey(Order, related_name='item_set')

and

cart = models.ForeignKey(ShoppingCart, related_name='item_set')