ASI consulting has created ER diagrams for both e-Opps and the entire iMIS for .NET table structure. These are for the 10.6.06 release. We generated these from the schema using a tool called ER Studio. I recommend this tool for anytime one must to understand what relationships are enforced between tables enforced at the database level. It is great help on iMIS conversions.

http://www.embarcadero.com/products/erstudio/index.html