Database reverse engineering (DBRE) recovers a database design using a semantic data model. Most of the existing works and tools for DBRE and database design specify relational database schemas with extended ER models. The Unified Modeling Language (UML) is a standard language for modeling software and database systems. We discuss how to extend the UML metamodel with elements for modeling relational dependencies. We also present techniques for converting structures of relational dependencies to UML constructs. The introduced metaelements and conversion techniques can be used in relational database design that is presented in the UML. They unify object-oriented software design and relational database design.