[okfn-help] sqlalchemy implementation of versioned domain model is go!

[Rufus Pollock]

Finally, after on and off work over the last few months I've got a full 
sqlalchemy implementation [1] of versioned domain model [2] working! Not 
only does this do basic object versioning but transparently supports 
versioning of many-to-many relationships and (historic) domain model 
traversal as well as 'caching' of the HEAD version of the model on the 
continuity objects for speedy performance (in most cases reads of the 
domain model are against HEAD).

Quite apart from the use of this in itself it means work can begin on 
moving CKAN from sqlobject to sqlalchemy which should mean substantial 
performance and feature improvments (and we can also look to integrate 
this into microfacts).

~rufus

[1]:<http://knowledgeforge.net/ckan/svn/vdm/trunk/vdm/sqlalchemy/>
[2]:<http://knowledgeforge.net/ckan/svn/vdm/trunk/>