Not sure if this will work for your use case, but I think this tool is super cool so I'll rep it: PlantUML is a tool that generates diagrams based on a markup language.

Database modeling UML has become a popular way to model databases. Not only are these diagrams a helpful visual tool for brainstorming and collaboration, but they can also help depict hierarchies, ...

Free tool may spur UML adoption Enterprise Lifecycle Management firm Telelogic is looking to spread the use of model-driven application development with the release this week of Telelogic Modeler ...

Some key features include UML modeling with object-model diagrams, code frame generation for C, C++ and Java, model import from Rational Rose, and integration with third-party requirements ...