Various embodiments herein each include at least one of systems, methods, and software for data migration, such as when migrating a database from one form to a next and as may be performed at a time of software system version migration. One example embodiment, in the form of a method, includes loading a database migration script that includes a prior class from a software system prior to an upgrade of the software system and a new class from the software system after the upgrade to the software system. The method proceeds by then calling methods of the prior class to copy database data from database tables impacted by the database migration script to a memory device and executing the database migration script. The method then calls methods of the new class to copy the database data from the memory device back to the database.