On Dec 6, 5:53 pm, Michael Bayer <mike...@zzzcomputing.com> wrote: > On Dec 6, 2010, at 11:52 AM, Ian Thompson wrote: > > > > > > > On Dec 6, 4:49 pm, Ian Thompson <quorn...@gmail.com> wrote: > >> I've generated a test data set and then want to have all of the > >> created objects and relationships available for reference easily. > >> To avoid possible pollution of this fixture I want to detach the > >> objects from the sessions to avoid them getting any updates applied. > > >> To do this I am attempting to load all data via joinedload and then > >> calling session.expunge_all: > > >> print assets['test_asset_1'].attributes # OK > > >> session.query(Asset).options(joinedload(Asset.asset_attributes)).populate_e > >> xisting().all() > >> session.expunge_all() > >> print assets['test_asset_1'].attributes # ERROR > > >> None of the relationships on the objects survive the expunge. > > >> sqlalchemy.orm.exc.DetachedInstanceError: > >> Parent instance <Asset at ...> is not bound to a Session; > >> lazy load operation of attribute 'asset_attributes' cannot proceed > > (cont...) > > Is there a correct way to detach all current data from the Session > > fully loading any relationships? (Small data set so memory is not a > > concern.) > > This use case seems like it would be more easily solved using a new Session > just for that load. To work with the objects detached, all "deferred" > attributes and lazy-loading "relationship" attributes which you will need to > access would need to either be eagerly loaded (there's now three ways to > eagerly load relationship() attributes), or otherwise accessed via > obj.attribute before the objects are expunged.
Hi Michael, thanks for your reply. I had thought by using joinedload (or eagerload) and populate_existing I would be doing an eager load of the specified relation. Also, in my example I do access the attributes relationship (with a print), then after the expunge the same fails. Is there a way I can ensure the data is preserved after expunging? Thanks Ian -- 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.
