http://techonthenet.com/oracle

http://www.ss64.com/oraplsql/

http://www.orafaq.com/

http://www.csee.umbc.edu/help/oracle8/server.815/a67842/06_errs.htm

http://www.dbaclick.com/forums/index.php?s=9a4559b30a7496d4bf96840ca2f0dda7

还有一个就是

dbforums.com