This is a hierarchical diagram of the software layers of OO4O.
At the base is Oracle Database.
On top of this is the Oracle Client Libraries (OCI, CORE, and NLS).
On top of this is the OO4O In-Process Automation Server.
Next is COM/DCOM.
Next, in parallel, are the C++ Class Libraries, the Oracle Data Control and Automation Controllers (VB, Excel, AS).
On top of these, standing at the top of the hierarchy, are the Data Aware ActiveX Controls.