On 25 huhti, 20:08, Alex Gaynor <alex.gay...@gmail.com> wrote: > This sounds like a reasonable request, I don't yet have an opinion on API > or anything. One tiny thing I'd like to note though, "change DeferredAttribute > to find all *other* DeferredAttributes". I don't think `finding` is the > right way to think about it, a `DeferredAttribute` with loadall semantics > should know about the specific set of objects that came from the queryset.
Searching for deferred fields already happens in some places (at least model.__init__ and model.save()). It would be possible to store the set of deferred fields in model._state on load from DB, but why record this information (with real possibility of messing it up if users do something like direct __dict__ assignments after load from DB) when there is a way to calculate the set of deferred fields on demand? One possible reason is to avoid the expense of the calculation, but the calculation costs very little compared to the DB query about to happen. I actually tried to store the set of deferred fields per instance when polishing the update_fields patch but the approach turned out to be uglier at least for the update_fields case. Now, if there would be some way to avoid the dynamic model subclassing used by deferred loading then storing the set of deferred fields per instance would be more than welcome. One possibility might be defining Model.__getattr__. If you end up in __getattr__ and the value isn't present in the model's __dict__ but the attname is present in the model._state.deferred_fields, then you know to load it from DB. I assume there are some reasons why this wasn't done in the first place... Maybe descriptors for custom fields would break or the above mentioned direct __dict__ access case would fail? - Anssi -- You received this message because you are subscribed to the Google Groups "Django developers" group. To unsubscribe from this group and stop receiving emails from it, send an email to django-developers+unsubscr...@googlegroups.com. To post to this group, send email to django-developers@googlegroups.com. Visit this group at http://groups.google.com/group/django-developers?hl=en. For more options, visit https://groups.google.com/groups/opt_out.
