On Feb 10, 2010, at 4:36 PM, Kent wrote: > Further, if I inspect the returned object *directly* after the call to > merge(), then aren't I guaranteed any Relations with use_list=True > have will have the same length, since that is the point of merge in > the first place?
you can assume the lengths are the same. I'm not sure though why you arent using the attributes.get_history() function I showed you which would allow you to see anything that changed directly. seems a lot simpler than what you're trying to do. > > That being the case, I can always simply correspond the merged index > with the original instances, correct (regardless of whether it is a > newly created object or was get()'ed from the database)? > > Correct? Yeah looking at the source its actually wholesale replacing the list on the target object so its a direct copy. I had the notion that it was appending to the list but I was incorrect. > > > On Feb 10, 4:28 pm, Kent <k...@retailarchitects.com> wrote: >> Very good, thanks. >> >> Although, I'm pretty sure I understand what you are saying, what >> exactly do you mean by "pending/transients"? >> >> 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. 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