this is close to what i have - bitemporal versions of same object. i dont have relation to succesors/predecessor (this is assumed from object_id being same).
the practice shows there are attributes - which u dont want to copy at all (dontcopy=list e.g. timestamps), - which u dont want to copy in depth (dontcopyme=true, e.g. refs to external things), - which u dont want the particular op to copy - e.g. because have been copied/changed by hand (dontcopy_now=list). There also the case of explicit m2m assoc_objects which are handled differently of all else. so it has to be some manual copy, or a very special setup of pickle-protocol-controls. seems this is a common requirement, so i may put mine somewhere in dbcook/. have fun svil On Wednesday 10 September 2008 11:39:43 Tim Jones wrote: > Michael, > > Thanks for your reply. > > The use case is configuration management. > > We have complex (SQLAlchemy) objects with many relationships which > we wish to up-version, i.e. we want an exact persistent copy > (attribute values and relationships) of the original object, but > with a different identity, which we will then modify. > > The original object and all its relationships should remain > unchanged (other than a relationship to its successor version). > > We would want the copied object and all its relationships saved to > the database before making changes to it. > > Regards, > > Tim > > > 2008/9/9 Michael Bayer <[EMAIL PROTECTED]> > > > copy.copy() is going to have issues since you'd be copying the > > _sa_state of the instance as well. "copying" an object that is > > SQLA mapped implies a particular use case in mind, depending on > > this use case is what would determine how you get your "copy". > > > > Would you like to get a "copy" that is simply the same object > > with the same identity, just as present in another session (in > > which case use merge()) ? > > > > Or would you like to get a "copy" that is a transient (no > > database identity) copy of that object, with all attributes > > except primary key attributes copied over ? ( in which case > > you'd use a copy constructor which possibly uses mapping metadata > > to traverse ) ? > > > > On Sep 9, 2008, at 2:16 PM, [EMAIL PROTECTED] wrote: > > > u can try: > > > from copy import copy > > > dest = copy(src) > > > it has pickle semantics, YMMV - i have not tried on SA objects. > > > i use my own, see my post in this thread with some (complex) > > > code: > > > > http://groups.google.com/group/sqlalchemy/tree/browse_frm/thread/ > >2369b78e0f8e21cb/4dd4979ca8501fba > > > > > On Tuesday 09 September 2008 18:59:09 picoplex wrote: > > >> Is there a quick way to copy an object (including all its > > >> relationships as well as its attributes)? > > >> > > >> Regards, > > >> > > >> Tim > > --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
