called the Unified Modeling Language (UML) (Booch et al., 1999). UML is the successor to a number of object-oriented analysis and design methods introduced in the 1980s and 1990s. The Object Management Group (OMG) is currently looking at the standardization of UML and it is anticipated that UML will be the de facto standard modeling language in the near future. Although we use the UML notation for drawing ER models, we continue to describe the concepts of ER models using traditional database terminology. In Section 25.7 we will provide a fuller discussion on UML. We also include a summary of two alternative diagrammatic notations for ER models in Appendix F.