John,
Rational Rose is designed to create diagrams of classes (i.e. business objects) rather than relational data. I recommend a tool such as XCase for modeling your data.
In the next version of the Framework, we'll be including a Rational Rose / Visual Modeler diagram of the Framework which you can use as a learning tool and/or to use as a basis for creating your class diagrams.
Regards,
Kevin McNeish
Eight-Time .NET MVP
VFP and iOS Author, Speaker & Trainer
Oak Leaf Enterprises, Inc.
Chief Architect, MM Framework
http://www.oakleafsd.com