AFAIK Bitcoin version 0.8.1 uses Berkeley Database. How it uses this DB? Bitcoin not need install database from from oracle.com.I hear that new Bitcoin change to Google database, only Wallet stay with Berkeley DB.
With BitcoinQt/bitcoind v0.8.x, the only BDB database is the wallet.dat. All prior versions used BDB for the blockchain and other databases as well. The client has statically linked everything so there is no installation of the database.
Beginning with v0.8.0 was LevelDB for the blockchain and everyrthing else other than wallet.dat
-
http://en.bitcoin.it/wiki/Data_directory#Directory_Contents