Access to database data in TestComplete uses the same approach for any database.
Primary option is ADO-based (Access Data Objects in the form of either native ADO COM objects or ADO Support extension provided by TestComplete. The latter is just a wrapper around native ADO). ADO requires either database-specific OE DB provider or ODBC driver. The bitness of OLE DB provider or ODBC driver must match TestComplete's bitness (or vise versa) and not necessarily must match the bitness of the database engine,