Overview

The ER modeling techniques in Chapter 6 are a good start at the methods you need for effective data modeling. This chapter expands on these basic techniques by extending them into the world of object orientation. Instead of modeling entities, now you are going to learn how to model objects. Hamlet was right: there are more things in heaven and earth than you can conceive but at least you can model more effectively what you can conceive.

The Unified Modeling Language (UML) is a notation that combines elements from the three major strands of OO design: Rumbaugh's OMT modeling [Rumbaugh et al. 1992], Booch's OO Analysis and Design [Booch 1994], and Jacobson's Objectory [Jacobson et al. 1992]. The UML shows every sign of becoming a standard. OMG has adopted the UML as the standard notation for object methods. The UML is ubiquitous in trade show presentations. Several professional books now cover the UML in greater or lesser detail in presenting their analysis and design methods [Douglass 1998; Eriksson and Penker 1997; Fowler, Jacobson, and Kendall 1997; Harmon and Watson 1998; Larman 1997; Muller, Nygard, and Crnkovic 1997; Quatrani 1997; Texel and Williams 1997].