Byte Designer is the emerging enterprise tool for designing databases at all levels of an organization, using the same concepts found in tools costing thousands of dollars! It's a powerful database design tool--with an advanced SQL editor and support for all major RDBMS--which can design complex systems.
Online documentation is found here: http://www.nipdata.com/faq/byte-designer-manual.html.
Updated on Nov 09 2015
Note: Although Finder indicates no version number for this application, the developer refers to it as version 2.3-151020.