On Mon, Feb 9, 2009 at 9:11 PM, Malcolm Tredinnick <malc...@pointy-stick.com > wrote:
> > On Sat, 2009-02-07 at 12:40 -0800, seanbrant wrote: > > Im have troubling figuring about a good solution for blog posts. I > > have created a ABC called Entry which Post, Link, Photo, Quote > > inherit. > > It would help others to define a few terms here before leaping into the > acronyms: ABC = "abstract base class", MTI = "multi-table inheritance", > I'm guessing. > > > > > I first tired it with MTI and set Entry.objects.all() as the queryset > > attribute. This will pass the list of Entry's to the template which I > > can iterate over. However I would like to style each type of Entry > > object a little different. Is there a way to know which type of Entry > > you are dealing with. > > Yes, by adding a field called "child_type" or something similar and > noting the content type of the most derived child, for example. > > > Then I tried ABC with the same models. Obviously including abstract > > True to the Base Entry class. With this approach I have know idea how > > to get a query set for all of these objects. > > You can't. They different types aren't related to each other. You need > to make "N" querysets and write your own version of the generic view > (remember, generic views are just an aid -- they don't fit all > requirements and not using them is always an option). > > > This seems like a fairly common use-case, > > Which is why it's been answered a number of times in the past. :-) > > Malcolm > > > > > If you choose to work with MTI I've worked up a bit of code that will automatically denormalize which subclass on object is, and load up the correct one when something is fetched from the ORM(note that this could turn a Base.objects.all() query into O(n) queries). In any event here is the code: http://dpaste.com/118723/ I plan to write up a proper blog post on it later at some point. Alex -- "I disapprove of what you say, but I will defend to the death your right to say it." --Voltaire "The people's good is the highest law."--Cicero --~--~---------~--~----~------------~-------~--~----~ 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 django-users+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/django-users?hl=en -~----------~----~----~----~------~----~------~--~---
