Hi, i'm evaluating diferent ways of connecting to db engines (db2, informix, etc), and AFAIK, the technologies, are:

1) Direct: the fastest method, but totally dependant on the db engine.
2) ODBC: generic. it can connect to any db engine that has an "odbc driver".
3) OLE DB: generic. a superset of ODBC, that can also connect to non SQL engines.
4) ADO: generic. a superset of OLE DB (wich encapsulates ODBC). Should be faster. It replaces OLE DB.

So, if all this is correct, can i use ODBC drivers, to connect by means of OLE DB and/or ADO? Any free Informix and DB2 drivers?