> On Sat, Feb 21, 2009 at 12:39 PM, Koen Bok <[email protected]> wrote: > > > Hey all. By tax law, invoice numbers need to always be unique and > > sequential. Anyone has an idea to approach this on AppEngine in a > > sensible way?
is it absolutely necessary for them to be exactly sequential, ie never have any holes? if there's any wiggle room on that, you could just use the built-in ids that are already allocated for all entities? (assuming you don't use key names.) for root entities, they're guaranteed to be unique across a given kind, and they're already being allocated, so they won't hurt scalability or performance. details: http://code.google.com/appengine/docs/python/datastore/keysandentitygroups.html#Kinds_Names_and_IDs http://groups.google.com/group/google-appengine/browse_thread/thread/dec83c2dbd9542e4 On Feb 22, 8:22 am, Dennis Peterson <[email protected]> wrote: > Although this is an interesting technical question, it might also be worth > taking a step back and asking whether a technology that doesn't really > implement transactions, except in very limited ways, is really the best > infrastructure for an accounting system. > > GAE is great but not necessarily the right tool for everything. true, but i disagree that it applies here. you're right that app engine doesn't provide fully global, distributed transactions, but not many highly scalable systems do. most applications can get a long way with the entity group local transactions and automatic id allocation that it does provide. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Google App Engine" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en -~----------~----~----~----~------~----~------~--~---
