DB2 UDB data models can now be accessed from within the popular UML modeling product, Rational Rose from Rational Software. This program can extract existing schemas into a logical model or can generate schemas directly from the model. There are many benefits in using a common design language (such as UML) for both object models and data models during the application development process.
Reference: Database Design for Smarties: Using UML for Data Modeling; Robert J. Muller; ISBN 1558605150