On Feb 10, 2010, at 4:28 PM, Kent wrote: > Very good, thanks. > > Although, I'm pretty sure I understand what you are saying, what > exactly do you mean by "pending/transients"?
see the description here: http://www.sqlalchemy.org/docs/session.html#quickie-intro-to-object-states > > > On Feb 10, 4:13 pm, Michael Bayer <mike...@zzzcomputing.com> wrote: >> On Feb 10, 2010, at 3:52 PM, Kent wrote: >> >> >> >>> If I understand you correctly, you are saying >>> object.list[0] will always cause creation (or fetch) of merged.list[0] >>> object.list[1] will always cause creation (or fetch) of merged.list[1] >>> etc. >> >>> There may be also more merged.list[2], [3], etc... >> >>> Correct? >> >>> This is the merge code 0.5.8: >> >>> if self.uselist: >>> dest_list = [] >>> for current in instances: >>> _recursive[(current, self)] = True >>> obj = session._merge(current, dont_load=dont_load, >>> _recursive=_recursive) >>> if obj is not None: >>> dest_list.append(obj) >>> if dont_load: >>> coll = attributes.init_collection(dest_state, >>> self.key) >>> for c in dest_list: >>> coll.append_without_event(c) >>> else: >>> getattr(dest.__class__, >>> self.key).impl._set_iterable(dest_state, dest_dict, dest_list) >> >>> Can I rely this implementation remaining ordered (deterministic), even >>> if it is re-written for optimization purposes or something? >> >> as long as you're using lists for your relations' collection implementations >> there's no reason the order of pending/transients would change. The objects >> coming back from the DB are not deterministic unless you add order_by to >> your relation, but thats why i said process those separately. >> >> >> >>> Also, I see that if obj is None, then dest_list.append() won't be >>> called, which would mess up my indexes. I am wondering is there a >>> more sure mechanism? Under what circumstances will obj be None? >> >> There's no codepath I can see where that can be None and there's no test >> that generates a None at that point, I'm not really sure why that check is >> there. I'd want to dig back to find its origins before removing it but >> _merge() pretty explicitly doesn't return None these days. >> >> >> >>> On Feb 10, 3:30 pm, Michael Bayer <mike...@zzzcomputing.com> wrote: >>>> On Feb 10, 2010, at 2:49 PM, Kent wrote: >> >>>>> After merge() returns, is there a way for me to pair each object in >>>>> the returned merge_obj with the object it was created from? >> >>>>> For example: >>>>> merged_obj = session.merge(object) >> >>>>> At the top level, it is trivial, merged_obj was created because of the >>>>> instance "object" >> >>>>> For single RelationProperties under the top level, it is fairly >>>>> simple, too. >> >>>>> That is: >> >>>>> merged.childattr was merged from object.childattr >> >>>>> Where it falls apart I think is if the RelationProperty.use_list == >>>>> True >> >>>>> merged.list came from object.list, but is there a way for me to >>>>> reference the original objects inside the list. >> >>>>> Did merged.list[0] come from object.list[0] or object.list[1] or >>>>> object_list[2]? >> >>>>> I particularly can't use the pk because it won't always be set (often >>>>> this will be a new record) >> >>>>> Any suggestions? >> >>>> the ordering of those lists (assuming they are lists and not sets) are >>>> deterministic, especially with regards to the pending objects that have >>>> been added as a result of your merge (i.e. the ones that wont have >>>> complete primary keys). I would match them up based on comparison of the >>>> list of instances that are transient/pending. >> >>>>> -- >>>>> You received this message because you are subscribed to the Google Groups >>>>> "sqlalchemy" group. >>>>> To post to this group, send email to sqlalch...@googlegroups.com. >>>>> To unsubscribe from this group, send email to >>>>> sqlalchemy+unsubscr...@googlegroups.com. >>>>> For more options, visit this group >>>>> athttp://groups.google.com/group/sqlalchemy?hl=en. >> >>> -- >>> You received this message because you are subscribed to the Google Groups >>> "sqlalchemy" group. >>> To post to this group, send email to sqlalch...@googlegroups.com. >>> To unsubscribe from this group, send email to >>> sqlalchemy+unsubscr...@googlegroups.com. >>> For more options, visit this group >>> athttp://groups.google.com/group/sqlalchemy?hl=en. >> >> > > -- > You received this message because you are subscribed to the Google Groups > "sqlalchemy" group. > To post to this group, send email to sqlalch...@googlegroups.com. > To unsubscribe from this group, send email to > sqlalchemy+unsubscr...@googlegroups.com. > For more options, visit this group at > http://groups.google.com/group/sqlalchemy?hl=en. > -- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To post to this group, send email to sqlalch...@googlegroups.com. To unsubscribe from this group, send email to sqlalchemy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en.
