OO4O uses OCI and not ODBC

extract from metalink :

Q: What is Oracle Objects for OLE?

Oracle Objects consists of three components:

* An OLE 2.0 Automation (InProcess) Server which provides an OLE
Automation interface to applications that support OLE automation
scripting such as Visual Basic (VB). This means that it can be used in
place of the database function calls normally used in VB and the syntax
used is as close as possible to VB's own database function calls
for easy porting. (Porting is not required as it can exist side-by-side
with exiting VB database code) Unlike VB's normal database function
calls which use ODBC, Oracle Objects for OLE is implemented using the
Oracle Call Interface. Because ODBC is not used, users are not subject
to the very serious limitations that ODBC places on Oracle users. (See
below for a description of these ODBC limitations.)


* The Oracle Data Control, which is a Visual Basic custom control (VBX).
This is designed to be a clone of Visual Basic's built-in data
control. The data control can be used in tandem with "Data Aware
Controls" (Grids such as Apex TrueGrid, or VB's Image Control for
example) which allow funneling of data to and from the data aware
control to the database with little or no coding. Rather than using
ODBC however, the Oracle Data Control uses OCI. You can replace the
VB data control used in exiting apps with the Oracle data control very
easily.


* Two C++ Class Libraries, one for Microsoft Foundation Classes (MFC)
and the other for Borland (OWL). These libraries encapsulate the
OLE Automation Server interface and objects, and also provide a
"Binder" class. These libraries do not require OLE knowledge nor
the OLE development kit. Their classes, members, and functions
are virtually identical to the ones found in Visual Basic.
The "Binder" classes are a significant improvement over the
Microsoft ODBC classes; the Microsoft classes force "early binding"
which means you must know your select statement at design time
before you can bind an object to it, while the Oracle classes will
allow "late binding" where the select statement is not known until
runtime.