On Jun 1, 2007, at 5:33 PM, [EMAIL PROTECTED] wrote:
> heh, if i remember how whole-heartly u defended this autodescend thing > some months ago... we didnt have generative behavior built into query so there was no way to conveniently get at an attribute based on a join. > > and more IMO, i think all these auto-guessing things in SA (and u have > many,many of them, and u like them) are _okay_ as far as there is a > way to disable them and require/specify all explicitly. i cant think of other places in SA that are literally "guessing". we have a lot of "assuming" as well as "defaults". these are not guesses because they are deterministic. a guess means you have more than one choice, and you pick one - randomly, or based on other things that were random (like dictionary ordering). it cant be predicted. if you map a relation from class A to B, we "assume" the join condition is based on the foreign keys between A and B's table. if I say A.join(B), the only possible way to join them unless explicitly stated is along their foreign keys (or I suppose you could say their column names, but that would be silly). thats not a guess...it will do the same thing every time. another example of a "default" is if you map a relation from A->A, it places the foreign key on the right side of the relation by default unless you specify "remote side". thats also not a guess. the topological sort that occurs during a flush - there is a degree of non-determinism there to the extent that more than one ordering exists for a given set of dependencies. but it *is* deterministic that the resulting ordering will be correct. theres no "guess" there, just that the specific ordering is just undefined, just like for a dictionary. if there were many, many guesses going on, we'd have many, many broken applications. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~----------~----~----~----~------~----~------~--~---
