Schema evolution is an unavoidable consequence of the application development lifecycle. The two primary schemas in an application, the client conceptual object model and the persistent database model, must co-evolve or risk quality, stability, and maintainability issues. We present MoDEF, an extension to Visual Studio that supports automatic evolution of object-relational mapping artifacts in the Microsoft Entity Framework. When starting with a valid mapping between client and store, MoDEF translates changes made to a client model into incremental changes to the store as an upgrade script, along with a new valid mapping to the new store. MoDEF mines the existing mapping for mapping patterns which MoDEF reuses for new client artifacts.