Sort of, but worse. If your database has no schema, any mistakes you make can accumulate subtle damage to the integrity of your data that you don't have any way

Sort of, but worse. If your database has no schema, any mistakes you make can accumulate subtle damage to the integrity of your data that you don't have any way of going back and fixing. I saw this happen in a Notes shop. Over time, some of the documents had been updated by many different versions of the code, until they were in such bizarre and unintended states that not even the developers could say what the correct app behavior should be anymore. If you are not migrating your data to your current schema, it will decay to garbage. If you are, you already have the old and new schema in your mind, so why not write them down and get some help from the tools? The other way out is to keep the authoritative version of your data in a store with a schema, and maintain a summary of it in your low-latency store that you can regenerate at need.