On May 21, 2010, at 9:12 AM, Michael Bayer wrote: > > On May 21, 2010, at 2:11 AM, Yang Zhang wrote: > >> >> It would be nice if this restriction could be lifted if explicitly >> requested somehow (__use_pk__ = False, and have those operations raise >> run-time exceptions if attempted). (As for why I'm using the ORM, it's >> basically because it affords many relatively minor benefits such as >> packaging up the tuple in its own object, a cleaner declaration syntax >> than Table(...), no need to use table.c.blah, custom constructors and >> methods, etc.) > > if you'd like to tell me what UPDATE statement should run during this > operation: > > > my_object_with_no_pk = Session.query(MyClassWithNoPk).filter(...).one() > > my_object_with_no_pk.some_attribute = 'new value' > > Session.commit() > > I'm all ears.
additionally, if you'd argue that such an operation would simply be not allowed, it still brings us no closer to determining how the identity map would function here. The ORM is archtected around an identity map model. The identity map is not just a "cache", its real purpose is so that objects associated with a session are unique relative to the row they represent in the database. I think here you really mean to be using the SQL expression language directly, since if your row has no primary key you really won't get any benefit from the ORM in any case. -- You received this message because you are subscribed to the Google Groups "sqlalchemy" 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/sqlalchemy?hl=en.
