One or more processors generate a view that identifies the data records of a first database having a back-level version. Instructions are received to migrate the data records from a back-level version to a new version of the data records. Responsive to receiving a query requesting data records of the first database, the version level of the requested data records is determined based on the generated view. Responsive to determining the requested data records are in the back-level version, a migration is performed on the requested data records including changes resulting in the new version of the requested data records. The requested data records are identified as changed to the new version of data records, and the new version of the requested data records are written to a pre-determined storage location and are provided to a requestor submitting the query.