CKAN: Ticket Query

#84: Revert support on versioned objects

rgrp — Thu, 23 Jul 2009 08:59:03 GMT

Basic revert in the classic wiki form is already support by purging a Revision. However may wish to support:

Cases where multiple objects changed in a revision but only want to revert 1 (low priority)
Want to revert but have reversion as a new revision of that object.

Seems low priority at present.

Cost: ?

#1135: Changeset model for vdm

rgrp — Thu, 12 May 2011 14:19:46 GMT

Move to Changeset model for vdm.

A changeset model is like an Audit-Log model in which we just record Changesets with Change-Objects rather than have Revision-Objects for each Object that is revisioned.

This change would also incorporate significant simplication of vdm.

#1136: Move to SessionExtension in vdm

rgrp — Thu, 12 May 2011 14:34:15 GMT

When vdm was created there was no SessionExtension so we use MapperExtension for doing revisioning. Now that SessionExtension? exists we should use it. We can also follow the existing SQLAlchemy recipe: <http://www.sqlalchemy.org/docs/orm/examples.html?highlight=versioning#versioned-objects>

#1137: Remove need for statefulness in vdm

rgrp — Thu, 12 May 2011 14:47:08 GMT

Statefulness, especially statefulness for relation (esp m2m) is cause of most of the complexity in vdm. It is required because, atm, revision objects have FKs to continuity objects.

This ticket proposes the following changes:

NB: this could be limited just to case of join tables (leaving state stuff on other tables)

Remove FKs from revision to continuity (or allow for them to be nullable).
- We could just limit this to m2m stuff
Delete of an object leads to:
- Deletion of continuity object
- Adding an entry in revision table with state set to deleted (we retain state on revision table)

If this is done we will no longer need to worry about filtering on state on relationships as join table will only contain "active" relationships.

If we do this on all tables we remove need for any state awareness in client (e.g. no need to filter tables on active state).

The only disadvantage of this change is that undeletion becomes more problematic (we have to recreate some continuity objects).