There isn't a whole lot to choose between ODBC and OLEDB when connecting to
Access. ODBC is based on an older standard that was not Microsoft-only and
there are a lot more ODBC drivers for third party products out there than
there are OLEDB providers. OLEDB is a more recent Microsoft-defined
standard. As far as I can remember, Microsoft's ODBC "Desktop database
drivers" are no longer "supported". Microsoft has, of course, moved on as
well and OLEDB is theoretically being replaced by ADO.NET, which is fine for
.NET programmers but has had no impact on the Office suite yet.

OLEDB can only be used from Word 2002 and later. ODBC works with earlier
versions - at least back to 97.

Off the top of my head, ODBC probably does not work properly with non-ANSI
Unicode data whereas the OLEDB provider probably does. The Jet ODBC driver
supports things called "ODBC escapes" which you probably don't need, wehreas
I think the OLEDB provider does not. ODBC may let you use some types of
query (partiicularly UNION queries) that OLEDB won't let you use - not for
any good reason as far as I know.

When issuing OpenDataSource calls, you may find that OLEDB restricts you to
a 255-character SQL string because of an error in Word, whereas ODBC will
probably allow the full 511 or whatever it is.

There's a third method, DDE, which needs to start Access to get its data but
allows you to use any table or query - including parameter queries
(ODBC/OLEDB can't use them), queries that reference user-defined functions,
queries that use certain functions such as those financial series functions,
and queries that use the old-style Jet SQL wildcards (* and ?). DDE is also
regarded as "deprecated" and insecure by Microsoft.

Peter Jamieson