On Fri, May 15, 2009 at 1:38 PM, Rusty Greer <[email protected]> wrote:
> > > On Fri, May 15, 2009 at 10:10 AM, Alex Gaynor <[email protected]>wrote: > >> >> >> On Fri, May 15, 2009 at 12:08 PM, Rusty Greer <[email protected]> wrote: >> >>> >>> >>> On Fri, May 15, 2009 at 9:57 AM, George Song <[email protected]> wrote: >>> >>>> >>>> On 5/15/2009 8:18 AM, Rusty Greer wrote: >>>> > >>>> > >>>> > I have something like this: >>>> > >>>> > class Class1(models.Model): >>>> > // lots of fields here >>>> > >>>> > class AbstractThing(models.Model): >>>> > // lots of fields here >>>> > class1field = model.ForeignKey(Class1) >>>> > class Meta: >>>> > abstract = True >>>> > >>>> > class ThingType1(AbstractThing): >>>> > // lots of fields here >>>> > >>>> > class ThingType2(AbstractThing): >>>> > // lots of fields here >>>> > >>>> > >>>> > in my template, i want to be able to do something like: >>>> > class1.abstractthing_set.all >>>> > >>>> > but that doesn't seem to work, i seem to have to do: >>>> > class1.thingtype1_set.all and class1.thingtype2_set.all >>>> > >>>> > does this make sense? am i missing something? >>>> > >>>> > any help would be appreciated. >>>> >>>> The pattern you describe should work fine. What exactly isn't working? >>>> >>>> -- >>>> George >>>> >>>> >>> from within the template, class1.abstractthing_set.all returns nothing, >>> class1.thingtype1_set.all returns exactly what is expected >>> >>> from python code, class1.abstractthing_set.all gives me an >>> AttributeError >>> >>> 'class1' object has no attribute 'abstractthing_set' >>> >>> >>> class1.thingtype1_set.all returns exactly what is expected >>> >>> i was hoping that the abstractthing_set would return all of the objects >>> of both thingtype1 and thingtype2 >>> >>> >>> >>> >> An abstract model doesn't exist in the database, therefore trying to get >> objects for it doesn't make sense, you either need to use concrete >> inheritance or manually query the individual models. >> >> Alex >> > > OK. I guess that makes sense. I was thinking more from an object point of > view. If I use a concrete base class instead of an abstract one, there will > be multiple tables combined to represent the data. So each fetch will be a > join of some number of tables. > > Because the tables are somewhat similar, would it be more efficient to have > 1 table with some unused fields or multiple tables and having to do a join? > > Rusty > > > > It depends, if there are times when you want to query against only one of them I'd probably have seperate tables, otherwise just one table with a type field or something. 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 [email protected] 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 -~----------~----~----~----~------~----~------~--~---
