Re: determining model subclass

[Andre Meyer]

hi Dave

finally, i have tried what you suggested. indeed, this is what is described
here.
and it works!

thanks a lot!
cheers
André


On Tue, Jul 8, 2008 at 3:13 PM, Chester <[EMAIL PROTECTED]> wrote:

>
> André,
> I'm assuming that you are using the Trunk version of Django because
> subclassing isn't supported in previous versions.
>
> Assuming that.
>
> You can either have Item be an Abstract class which does not act like
> a table but just a parent class containing common items. (this is not
> what you are trying...)
>
> Or
>
> Each sub class is a seperate model from Item (assuming this is what
> you want).   From the documentation you should be able to do the
> following:
>
> items = Item.objects.all()
> for item in items:
>  try:
>x = Item.task
>type = "Task"
>  except:
>try:
>   x = Item.event
>   type = "Event"
>except:
>   type = "Item"
>  Do something pertaining to the item type
>
>
> I haven't tried this but according to the docs it should work You
> should also fill in the correct exception.  I just don't know what it
> is.
>
> Hope it helps.
>
> Dave.
>
>
>
>
>
>
> On Jul 8, 2:12 am, "Andre Meyer" <[EMAIL PROTECTED]> wrote:
> > hi all
> >
> > is it possible to determine the subclass of a model instance?
> >
> > what i mean is this:
> > if you have a (n abstract) model class and two subclasses, like
> >
> > class Item(models.Model):
> > pass
> >
> > class Task(Item):
> > pass
> >
> > class Event(Item):
> > pass
> >
> > and you retrieve
> >
> > items = Item.objects.all()
> >
> > how can you know whether the items are either tasks or events?
> >
> > items[0].__class__ returns just .
> >
> > thanks for sharing your insights
> > regards
> > André
> >
>

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Re: determining model subclass

[David K]

Dave's method is what I also use.  I was hoping someone would come up
with an easier way, but I think it is a limitation of the way the
database tables are created in multitable inheritance.

David

On Jul 8, 6:13 am, Chester <[EMAIL PROTECTED]> wrote:
> André,
> I'm assuming that you are using the Trunk version of Django because
> subclassing isn't supported in previous versions.
>
> Assuming that.
>
> You can either have Item be an Abstract class which does not act like
> a table but just a parent class containing common items. (this is not
> what you are trying...)
>
> Or
>
> Each sub class is a seperate model from Item (assuming this is what
> you want).   From the documentation you should be able to do the
> following:
>
> items = Item.objects.all()
> for item in items:
>   try:
> x = Item.task
> type = "Task"
>   except:
> try:
>x = Item.event
>type = "Event"
> except:
>type = "Item"
>   Do something pertaining to the item type
>
> I haven't tried this but according to the docs it should work You
> should also fill in the correct exception.  I just don't know what it
> is.
>
> Hope it helps.
>
> Dave.
>
> On Jul 8, 2:12 am, "Andre Meyer" <[EMAIL PROTECTED]> wrote:
>
> > hi all
>
> > is it possible to determine the subclass of a model instance?
>
> > what i mean is this:
> > if you have a (n abstract) model class and two subclasses, like
>
> > class Item(models.Model):
> > pass
>
> > class Task(Item):
> > pass
>
> > class Event(Item):
> > pass
>
> > and you retrieve
>
> > items = Item.objects.all()
>
> > how can you know whether the items are either tasks or events?
>
> > items[0].__class__ returns just .
>
> > thanks for sharing your insights
> > regards
> > André

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Re: determining model subclass

[Chester]

André,
I'm assuming that you are using the Trunk version of Django because
subclassing isn't supported in previous versions.

Assuming that.

You can either have Item be an Abstract class which does not act like
a table but just a parent class containing common items. (this is not
what you are trying...)

Or

Each sub class is a seperate model from Item (assuming this is what
you want).   From the documentation you should be able to do the
following:

items = Item.objects.all()
for item in items:
  try:
x = Item.task
type = "Task"
  except:
try:
   x = Item.event
   type = "Event"
except:
   type = "Item"
  Do something pertaining to the item type


I haven't tried this but according to the docs it should work You
should also fill in the correct exception.  I just don't know what it
is.

Hope it helps.

Dave.






On Jul 8, 2:12 am, "Andre Meyer" <[EMAIL PROTECTED]> wrote:
> hi all
>
> is it possible to determine the subclass of a model instance?
>
> what i mean is this:
> if you have a (n abstract) model class and two subclasses, like
>
> class Item(models.Model):
>     pass
>
> class Task(Item):
>     pass
>
> class Event(Item):
>     pass
>
> and you retrieve
>
> items = Item.objects.all()
>
> how can you know whether the items are either tasks or events?
>
> items[0].__class__ returns just .
>
> thanks for sharing your insights
> regards
> André
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