You probably have a list of products somewhere, right? (from a form or other input). Couldn't you just do
sum([p.price for p in products]) where products is that list?? On Fri, Aug 29, 2008 at 9:08 PM, Koen Bok <[EMAIL PROTECTED]> wrote: > > I'd like to build relations with objects without saving to pre- > determine the price for a proposed order based on a set of products. > But when I add a Product project to the Order, I first have to save > the Order. Is there any way around this? > > Example: > > class Order(Model): > id = models.AutoField(primary_key=True) > number = models.IntegerField() > > def total(self): > return sum([p.price for p in self.product_set]) > > class Product(Model): > id = models.AutoField(primary_key=True) > order = models.ForeignKey(Order) > price = models.DecimalField() > > order = Order(number=1) > > # Now the nex line throws an error if we did not save the order here > order.product_set.create(Product(price=20.0)) > > assert order.total() == 20.0 > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to django-users@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/django-users?hl=en -~----------~----~----~----~------~----~------~--~---
