30.1. Design Tools

Current design tools consist mainly of graphical tools that create design diagrams. Design tools are sometimes embedded in a computer-aided software engineering (CASE) tool with broader functions; some vendors advertise standalone design tools as CASE tools. Graphical design tools generally allow you to express a design in common graphical notations: UML, architecture block diagrams, hierarchy charts, entity relationship diagrams, or class diagrams. Some graphical design tools support only one notation. Others support a variety.

Cross-Reference

For details on design, see Chapters 5 through 9.

In one sense, these design tools are just fancy drawing packages. Using a simple graphics package or pencil and paper, you can draw everything that the tool can draw. But the tools offer valuable capabilities that a simple graphics package can't. If you've drawn a bubble chart and you delete a bubble, a graphical design tool will automatically rearrange the other bubbles, including connecting arrows and lower-level bubbles connected to the bubble. The tool takes care of the housekeeping when you add a bubble, too. A design tool can enable you to move between higher and lower levels of abstraction. A design tool will check the consistency of your design, and some tools can create code directly from your design.