я в свое время работал под ODAC но оракловый клиент все равно стоял.

ODAC работает так:

Applications which rely on BDE to gain access to Oracle database follow this path of interconnections:

[Oracle server] <-> [SQL*Net] <-> [OCI] <-> [SQL Links] <-> [BDE] <-> [Client application]

ODAC works directly through the Oracle Call Interface, which eliminates BDE and SQL Links from above chain as follows:

[Oracle server] <-> [SQL*Net] <-> [OCI] <-> [Client application]