On Sep 7, 2010, at 10:12 AM, Kent Bower wrote: > Mike, in your proof of concept, when __getstate__ detected transient, why did > you need to make a copy of self.__dict__? "self.__dict__.copy()"
i was modifying the __dict__ from what would be expected in a non-serialized object, so that was to leave the original object being serialized unchanged. > > > > On 9/6/2010 2:35 PM, Michael Bayer wrote: >> >> On Sep 6, 2010, at 2:11 PM, Kent Bower wrote: >> >>> Also, I was hoping you would tell me whether this would be a candidate for >>> subclassing InstrumentedAttribute? Would that make more sense or providing >>> custom __getstate__ & __setstate__ ? >> __getstate__ / __setstate__ are pretty much what I like to use for pickle >> stuff, unless some exotic situation makes me have to use __reduce__. One >> problem with the recipe is that theres no 'deferred' loading of attributes. >> So in that sense playing with InstrumentedAttribute would give you a chance >> to put a callable in there that does what you want. >> >> There is also the possibility that __setstate__ can load up callables into >> the instance_state using state.set_callable(). This is a callable that >> triggers when you access the attribute that is otherwise None. There's a >> little bit of fanfare required to get that callable to assign to the >> attribute in the right way. Attached is an example of that. This is all >> a little more shaky since the state/callable API isn't really public. >> Hasn't changed for awhile but there's no guarantee. >> >> >> >> >> >> >>> Thanks for your help, hopefully I'll be able to contribute such a recipe. >>> >>> Kent >>> >>> >>> >>>>> Since sqla won't load that for me in the case of transient, I need to >>>>> load the relation manually (unless you feel like enhancing that as well). >>>> its not an enhancement - it was a broken behavior that was specifically >>>> removed. The transient object has no session, so therefore no SQL can be >>>> emitted - there's no context established. >>>> >>>> >>>> >>>>> Now I can manually emulate the obj being persistent with your changes for >>>>> >>>>> On Sep 6, 2010, at 10:58 AM, Michael Bayer <mike...@zzzcomputing.com> >>>>> wrote: >>>>> >>>>>> On Sep 6, 2010, at 9:06 AM, Kent wrote: >>>>>> >>>>>>> with_parent seems to add a join condition. >>>>>> OK, so I guess you read the docs which is why you thought it joined and >>>>>> why you didn't realize it doesn't work for transient. r20b6ce05f194 >>>>>> changes all that so that with_parent() accepts transient objects and >>>>>> will do the "look at the attributes" thing. The docs are updated as >>>>>> this method does use the lazy loader SQL mechanism, not a join. >>>>>> >>>>>> >>>>>> >>>>>>> Is there a way to get at >>>>>>> the query object that would be rendered from a lazy load (or what >>>>>>> "subqueryload" would render on the subsequent load), but on a >>>>>>> transient object, if i supply the session? >>>>>>> >>>>>>> even though not "recommended", can it make sqla believe my transient >>>>>>> object is detached by setting its state key? >>>>>>> >>>>>>> There are reasons i do not want to add this to the session and >>>>>>> disabling autoflush would also cause problems. >>>>>>> >>>>>>> >>>>>>> >>>>>>> On Sep 3, 9:58 am, Michael Bayer <mike...@zzzcomputing.com> wrote: >>>>>>>> On Sep 3, 2010, at 9:36 AM, Kent wrote: >>>>>>>> >>>>>>>>> For the case of customerid = '7', that is a simple problem, but when >>>>>>>>> it is a more complex join condition, we only wanted to define this >>>>>>>>> condition in one single place in our application (namely, the orm). >>>>>>>>> That way, if or when that changes, developers don't need to search for >>>>>>>>> other places in the app that needed to manually duplicate the logic of >>>>>>>>> the orm join condition. >>>>>>>>> If I supplied the DBSession to sqla, it would know how to create the >>>>>>>>> proper Query object for this lazyload. Can you point me in the right >>>>>>>>> direction (even if where you point me is not currently part of the >>>>>>>>> public API)? >>>>>>>> Query has the with_parent() method for this use case. >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>>> Thanks again, >>>>>>>>> Kent >>>>>>>>> -- >>>>>>>>> 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. >>>>>> >>>>> -- >>>>> 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. >>>> >>> -- >>> 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. -- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. 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