I’ve released a first stab at a bit of XSLT that will transform the Database Model Diagram XML Output from the Orthogonal Toolbox into SQL DDL:
http://www.orthogonalsoftware.com/files/OTERtoSQL.xslt
You may need to tweak it a bit for your DBMS (I have only really used MS SQL Server as my test platform), but it should be mostly compatible.
This would be useful if you are stuck with Visio Professional (which won’t forward engineer databases at all) or if you want more control over DDL generation in Visio.
Any comments or suggestions would be welcome.