Hallöchen! Russell Keith-Magee writes:
> On Tue, Dec 21, 2010 at 8:33 PM, Torsten Bronger > <bron...@physik.rwth-aachen.de> wrote: >> Hallöchen! >> >> Marc Aymerich writes: >> >>> [...] >>> >>> Morgan, take a look at the inheritanceManager of this app: >>> https://github.com/carljm/django-model-utils#readme >> >> Is anything like this planned for core Django? It's the third or >> forth time I see someone needing it. > > [...] > > At the time, we decided to omit support for 'narrowing' (to use > the CORBA parlance) as part of the default feature set because it > requires either: > > a) table overhead to store the type of the child instance > b) an expensive query (or list of queries) that isn't obviously expensive. > > We weren't (and I'm still not) willing to impose either of these > overheads by default. I must clarify my use of "core Django" above. Of course this may well be realised in contrib/ as an optional feature. However, I'd love to see it in the Django release with explanations in the Django docs. > The good news is that either strategy is easy to implement without > modifications to core. I've got several classes in production that do > narrowing-like behavior (for the record, both using strategy (a)). (a) is the way to go in my opinion. I think the table overhead itself is not so much of a problem but any migration of old databases necessary due to it. So, I understand that it cannot be default behaviour. > With a bit of extra effort, this should be easy to turn into a mixin > that could be shared as part of a third-party support library, much as > django-treebeard or django-mptt provide model support extensions > implementing tree-like structures. As somebody who has strugged with this problem for a along time and having seen a couple of solutions along the road, I find https://github.com/carljm/django-model-utils quite appealing and finished. Tschö, Torsten. -- Torsten Bronger, aquisgrana, europa vetus Jabber ID: torsten.bron...@jabber.rwth-aachen.de or http://bronger-jmp.appspot.com -- You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to django-us...@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.
