The automatic generation of components from abstract models greatly facilitates information systems evolution, as changes to the model are easier to comprehend than changes to program code or service definitions. At each evolutionary step, however, any data already held in the system must be migrated to the new version, and to do this manually can be time-consuming and error-prone. This paper shows that it is possible to generate, automatically, an appropriate sequence of data transformations. It shows also how the applicability of a sequence of transformations may be calculated in advance, and used to check that a proposed evolution will preserve semantic integrity.