Business DB Meta-Model

will update as more detail become clear . . .


Also see:
http://www.salesforce.com/us/developer/docs/api/Content/sforce_api_erd_majors.htm
http://www.salesforce.com/us/developer/docs/api/Content/sforce_api_erd_activities.htm
http://www.salesforce.com/us/developer/docs/api/Content/sforce_api_erd_products.htm
http://www.salesforce.com/us/developer/docs/api/Content/sforce_api_erd_support.htm
http://www.salesforce.com/us/developer/docs/api/Content/sforce_api_erd_recordtype.htm