Something I understood only recently is that a DB is an API. You can add fields/tables to it easily but changes should always be backwards-compatible (if you ca

Something I understood only recently is that a DB is an API. You can add fields/tables to it easily but changes should always be backwards-compatible (if you care about availability). Only when all the clients have been upgraded can the old fields/tables be removed. Most deploys should be: 1. Adding fields/tables 2. Replace all clients 3. Remove old fields/tables In the case of a rename triggers should be used to duplicate data between step 1 and 3.