Even this is vastly over-engineered. Just have a target schema definition somewhere, and use a schema diff tool to generate the changes you nee on demand. No

Even this is vastly over-engineered. Just have a target schema definition somewhere, and use a schema diff tool to generate the changes you nee on demand. No need for version numbers at all. No need to run through change scripts to set up a database from scratch. Almost no need to manually write scripts.