In case of Library activity I'm going to follow simple rules: * use local datastore API to search/filter objects * use remote datastore API(in some way) to search/filter objects from remote users(sources) * use telepathy tubes for notifying users about changes * sync shared objects while opening Library activity or manually
So, dirty objects is not a huge problem for Library On Mon, May 04, 2009 at 03:15:41PM -0500, James Simmons wrote: > Carol, > > I see sharing the catalog as a read-only thing. I don't know what > Aleksey has in mind for Library. Even if that wasn't true, a database > is not necessary. There is a framework called Prevayler that handles > in-memory databases in such a way that you can lose power without losing > updates. I've used that framework in Java and I believe there is an > implementation for Python as well. I doubt I would need it though. > > I think of this as being an electronic card catalog for one's personal > library. I'm not doing airline reservations, or dealing with more data > than will easily fit in memory. If someone's battery dies while they're > adding cards to the catalog they'll lose their work but the old > directory entry should survive. > > As a user I would not want to need external software to make my Activity > work. I have experienced this with Read Etexts and the speech function. > Read Etexts has supported TTS with highlighting for months, but getting > the needed external (outside the Activity bundle) software on everyone's > XO is a whole other problem, that will take a lot longer to solve. If > there was a way to avoid that I would have. > > James Simmons > > > Carol Farlow Lerche wrote: >> You would need to reinvent ACID updates if you shared the catalog. >> >> On Mon, May 4, 2009 at 12:34 PM, James Simmons >> <jim.simm...@walgreens.com <mailto:jim.simm...@walgreens.com>> wrote: >> >> Carol, >> >> I would not use sqllite 3. The metadata for several hundred books >> could easily fit in memory. It would basically be a good sized >> spreadsheet. Python has a "pickling" feature which can save a >> bunch of objects in memory in a single file that can be easily >> reloaded into memory. I could store the pickle file as a Journal >> entry. I would not try to recreate ALL of Calibre, just the parts >> I would find the most useful. That way the Activity could be >> entirely self contained. >> >> James Simmons >> >> >> Carol Farlow Lerche wrote: >> >> Calibre makes a sqlite3 database which is the basis for its >> display. It seems to have a reasonable schema. (An easy way >> to examine it is with the Sqlite Manger, an excellent Firefox >> add-on if you haven't already discovered it). >> >> >> >> > -- Aleksey _______________________________________________ IAEP -- It's An Education Project (not a laptop project!) IAEP@lists.sugarlabs.org http://lists.sugarlabs.org/listinfo/iaep