I've lost some Rollback Segments, how can I get my DB back

Restart your database with following INIT.ORA parameter _Corrupted_rollback_segments = (rbs01, rbs01, rbs03, rbs04) if one of your rollback segments is corrupted.

You can then drop the corrupted rollback segments and create it from scratch.

Caution is advised when enabling this parameter, as uncommitted transactions will be marked as committed.

One can very well end up with lost or inconsistent data!!!

Please contact Oracle Support before using it.
 _Corrupted_rollback_segments = (rbs01, rbs01, rbs03, rbs04) 

How to fix: ERROR 1045 (28000): Access denied for user ‘root’@’localhost’ (using password: YES)

Open your terminal and type mysql -u root -p Enter your password. Hopefully your MySQL is logged in now.