When information systems managed by different organizations are integrated, the different parties often must collaborate to define a migration system that transforms the data from one data model to the other. Such a migration step is a common source of system failures. We present a migration language to define transformation definitions for real-time unidirectional data migration (i.e. “importing”), from a relational schema to a data model defined in the Alan modeling language. This migration language has been designed to be transparent (simple to inspect and validate), easy to debug in case of failures, but expressive enough to support common patterns encountered in real-world projects. We examine three different case studies based on real-world software projects to illustrate the characteristics, capabilities, and limitations of the tool.