[IAEP] Library Activity

[James Simmons]

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.simmons at walgreens.com <mailto:jim.simmons at 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).
>
>
>
>

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