Is there an API I can use to program a flow diagram?

My need to develop a table flow diagram from database data collected in a excel spread sheet. I need to parse the table joins and generate a flow diagram. The program is an attempt to keep our diagrams up-to-date.

Does anyone know of an API I can use to accomplish this?

Thanks,
Anselm

I am not sure there is an API, but see below or there are some flow diagram apps out there.
http://www.borland.com/together/

I am not looking to convert classes or a database schema using a modeling tool, but rather looking for a way to write a program that constructs the diagram. Does anyone know anything out there that allows me to do this, please let me know.

Sure, this is all you need.