Changes between Version 7 and Version 8 of ModelInheritance

Timestamp:

Feb 25, 2006, 2:21:16 PM (18 years ago)

Author:

anonymous

Comment:

--

ModelInheritance

@@ -96 +96 @@
 Imagine we have more than one subclass of {{{Place}}} though. The join clause and the column list would get pretty hefty. This could obviously get unmanageable pretty quickly.
 
+''
+I think some dbs have a maximum number of joins (something like 16), and even within the maximum, the query optimizer will either spend a while deciding which way to best join the tables or it will give up and choose the wrong way quickly.  This wording is FUD-- I'll try to find specifics.  --jdunck
+''
+
 Another option is to lazily load objects like {{{Restaurant}}} and {{{ItalianRestaurant}}} while we're iterating over {{{Place.objects.all()}}}, but that requires a ''lot'' of database queries. Either way, doing this will be expensive, and api should reflect that. You're much better off ''just'' using {{{Place}}}s fields if you are going to iterate over {{{Place.objects.all()}}}