ThoughtLeadr uses Bip's approach. Its essential lazy schema migration. On Wed, Sep 19, 2012 at 3:03 PM, Reid Draper <reiddra...@gmail.com> wrote:
> I have also used Bip's method and found it successful. You do need to be > careful to make sure > all reads of your data go through this upgrade-path, but that is easy once > you realize it :). > > > Reid > > On Sep 19, 2012, at 5:44 PM, Bip Thelin <b...@kivra.com> wrote: > > We use a technique that works well for our use case: > We store everything as JSON and use the erlang-client, for every object we > store we add an opaque schema_version tag to the JSON and then in our model > encode/decode routine we parse this schema_version and if the version is > not the latest according to the model we recurse and upgrade the payload > all the way up to the current version and then return the new object to the > client and spawn an async process that saves the new object back. > > So for instance an object is at schema_version 1 when it get's read. The > model is now on version 5 there will be five functions, i.e: > upgrade_version(2, Payload) -> > do_something(); > upgrade_version(3, Payload) -> > etc... > > every function knows how to upgrade itself from it's former version so > fast forwarding through version is easy and every object will get upgraded > eventually (if the get read). > > -- > Bip Thelin > > KIVRA | Lugnets Allé 1 | 120 33 Stockholm > Tel 08-533 335 37 | Mob 0735-18 18 90 > www.kivra.com > > > > > On 19 sep 2012, at 00:55, Allen Johnson <akjohnso...@gmail.com> wrote: > > Hey everyone, > > I'm beginning to experiment with Riak and I'm trying to better > understand how to model my data. One question I have at the moment is > how to evolve my data with a data store such as Riak? I know that > it's schema-less and that I can add new fields as needed but I'm > thinking more about the existing documents. > > For example, say hypothetically, that I have a fairly successful > riak-based app. As the application code continues to evolve over > several versions I begin to find a "better" way to model my data. By > this time I have already stored many, many documents. What is the > appropriate path here? Do I version my documents with metadata and > rely on my application code to continue to deal with old-style > documents -- or do I perform some sort of bulk transformation on these > existing documents? > > Thanks, > Allen > > _______________________________________________ > riak-users mailing list > riak-users@lists.basho.com > http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com > > > _______________________________________________ > riak-users mailing list > riak-users@lists.basho.com > http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com > > > > _______________________________________________ > riak-users mailing list > riak-users@lists.basho.com > http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com > > -- Cheers, Todd Cullen | Founder & CEO of ThoughtLeadr 177 Post Street, #550 SF 94108 e. t...@thoughtleadr.com p. 415-254-0787 twitter: @shakakai <http://www.twitter.com/shakakai> skype: todd.cullen Fast Company covers ThoughtLeadr<http://www.fastcocreate.com/1680828/imgur-blurs-line-between-memes-and-ads-with-lipton-briskscumbag-steve-hybrid>
_______________________________________________ riak-users mailing list riak-users@lists.basho.com http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com
