This is a follow-up to the design summit discussion about DB migrations. There was concern about the undo-ability of some migrations. The specific example cited was removal of a column. Could that be done with the following three migrations, each undo-able? First, change the code to keep writing the column but no longer read the column. Second migration changes the code to neither read nor write the column. Third migration physically removes the column. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.openstack.org/pipermail/openstack-dev/attachments/20131113/07636359/attachment.html>