On Jan 26, 2006, at 12:26 PM, Joseph Kocherhans wrote:
http://code.djangoproject.com/wiki/ModelInheritance
Thanks for doing this, Joseph! It looks really good, too, but here
are the (inevitable) nitpicks:
1. Modeling parent relations in SQL: #3 seems to make the most sense
for me -- I can't think of a case in a one2one where the child id
would need to differ from the parent id. Also::
CREATE TABLE "myapp_restaurant" (
"id" integer NOT NULL PRIMARY KEY REFERENCES
"myapp_places" ("id"),
"description" text NOT NULL
);
works just fine (at least in Postgres); I'd suggest that SQL
relations be used explicitly here.
2. Modeling joins in SQL / lookup API: my general take on this is
"make it explicit". If I ask for places, give me a list of places
and don't bother looking up restaurants. So::
``place_instance.description`` should raise an ``AttributeError``
regardless if weather or not it is actually a restaurant.
However, there means there should be a way, given a Place, to get a
Restaurant; I would suggest::
>>> p = Place.objects.get(pk=1)
>>> r = Restaurant(p)
>>> i = ItalianRestaurant(p) # or ...(r)
(I suggest this syntax since it looks like exactly like casting --
``foo = int(bar)``).
Other than that, this looks GREAT.
Jacob
