My understanding is that people use Delphix (https://www.delphix.com/) for this reason partly. Adam Leventhal — correct?

You are right that this could be a potential application of Noms, but I think you’d want developers to feel that they are programming against same db in prod as in test, which means you need to somehow emulate the various db interfaces, right?

I think this is why the Delphix approach (as I understand it) is clever for this purpose. You fork/version the filesystem under the DB rather than the DB itself.