Lightweight Transformation of Data Models from SQL Schemas to UML-ER

Data modeling is an essential part of the software development process, and together with application modeling forms the core of the model-driven approach to software engineering. While UML is considered the standard for application modeling, there is really no corresponding open standard for data modeling. In this paper, we propose an approach and a tool to help bridge the gap between application and data modeling based on source transformation technology. In this paper we introduce SQL2XMI, a tool that automatically transforms an SQL schema into a UML-ER model expressed in XML Meta Interchange (XMI) 2.1, which is specifically designed to support interchange of UML models. By bringing the data model to the UML world, our tool enables the manipulation and integration of both data and application models using the same UML-based tools in an interoperable way. While SQL2XMI was initially created to support our work in software comprehension, the approach we have used can be generalized to recover a rich UML-ER model from any SQL schema to any XMI 2.x format, and can easily be extended to support code engineering by automatically generating SQL schemas from an XMI 2.x file.