Changing the mode to 'nr' was the trick. I didn't see that mode in the docs! Thanks for the input there.
On Jun 13, 8:03 pm, Christopher Lee <l...@chem.ucla.edu> wrote: > On Jun 13, 2009, at 5:52 PM, Kenny Daily wrote: > > > > > First, that would be great to use the Graph instead, so I can query > > it. It works the same when adding/binding attributes? I know the > > difference in constructing it. > > Yes, you save the schema of the Graph to worldbase in the same basic > way as for a Mapping, just using a metabase.OneToManyRelation schema > object instead of OneToOneRelation... > > > > > BUT I tried to add the close() and still get the same problem. So > > where do I add the close call? Immediately after my for... loop, after > > adding the mapping resource to the worldbase, or before/after the > > worldbase.commit()? I actually am getting an EOFerror, which to me > > does indicate that a buffer was not flushed to a file. > > I just noticed that you are using mode 'ww' which means that the > Mapping will not only be opened initially in write mode, it will also > be opened in write mode whenever it is unpickled in the future. Is > that really what you want? Given that you're having trouble reopening > this Mapping successfully, I think you ought to switch to 'nr', which > means > - initially, open in mode 'n', creating a completely new shelve file; > if an existing shelve file is present, its contents will be deleted, > so you know you are starting from scratch. > > - when the Mapping is unpickled in the future it will open in mode > 'r', i.e. read-only. That way the contents should remain exactly what > they were when you first created them. > > I am wondering whether some side-effects of your first attempt to > create this shelve file without closing it may be persisting and > screwing up subsequent attempts to write it correctly. (I know that > on Windows this could cause long-lasting mayhem). If I were you, I'd > delete the existing file and start over from scratch, maybe with a > different filename just to be on the paranoid side. > > A second, more fundamental piece of advice for getting things working > with worldbase: do this in two steps. It seems like you're trying to > accomplish two steps in one script: > > 1. create the Mapping and save it successfully to disk; > > 2. add this resource to worldbase. > > Since your script proceeds directly to step 2 without first checking > that step 1 actually worked, this makes it much harder to debug. I > suggest that you just try to do step 1, then check that it succeeded > by reopening it in read-only mode, and verifying that its contents are > what you'd expect. Once you are able to re-open that Mapping read- > only whenever you want, adding it to worldbase should be trivial. > > -- Chris --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "pygr-dev" group. To post to this group, send email to pygr-dev@googlegroups.com To unsubscribe from this group, send email to pygr-dev+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/pygr-dev?hl=en -~----------~----~----~----~------~----~------~--~---
