Maybe I can help Luc? I had similar questions once, because I started learning Django while deploying with a legacy database.
On 8 fev, 20:31, Luc Saffre <luc.saf...@gmx.net> wrote: > You cannot ask user code to not even look at invalid data. I'm > not allergic to exceptions, but raising an exception when I ask for the > content of a field is not appropriate behaviour. > > Luc Raising the exception *is* appropriate behaviour, because when you access `a_model.b_related`, and `b_related` is a ForeignKey, you're not really accessing a value, but doing a lookup. This is consistent with both the ER and ORM model, where FK's are pointers, not values. And a FK pointing to a non-existant row *is* an exception. It means broken data. If you want the content of the *field*, what you really should check is `a_model.b_related_id is None`, which is checking if a pointer was set. Still, it doesn't guarantee that this pointer leads to anywhere valid. That's why dealing with the exception is a common idiom, "fail early, fail loudly", and particularly useful in this case to maintain DB consistency. I hope it helps in understanding the rationale behind the behaviour and why Luke marked as invalid. -- You received this message because you are subscribed to the Google Groups "Django developers" group. To post to this group, send email to django-develop...@googlegroups.com. To unsubscribe from this group, send email to django-developers+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/django-developers?hl=en.
