You can find original user password in table USER$. Because of security improvements it is not exposed in DBA_USERS view anymore since version 10G. Moreover password is hashed so once set you are not able to know original value. Access to USER$ is as well very restricted.
Hakan factor
The Hakan factor is used to unique map rows in a Bitmap Index to the rows in the base table. This factor is related to the max number of rows that can be stored in a single block of a table. Several factors like the column type and not null constraints influence the Hakan factor. The factor will also be recalculated when a table is modified until there is the first bitmap Index is created. Than the Hakan factor has to be protected for the existing bitmap indexes.
If a new table created to exchange data with the partitioned table, with a table layout, that include columns added after the bitmap index creation on the partitioned table, will most likely result in a different Hakan factor.
Errors
If the Hakan Factor do not match during exchange partitions, the prognosis is either of the error messages below:
The error can appear only if you exchange a partition with bitmap indexes
Autonomous transaction – is an independent transaction called from another transaction which is the main transaction.
Features of autonomous transaction
Special pragma AUTONOMOUS_TRANSACTION is introduced in PL/SQL. The pragma instructs the database that executed code is to be executed as new autonomous transaction independent from main transaction.