SQL

To list all the tables

 SELECT table_name
 FROM all_tables;

 SELECT SYSDATE FROM DUAL;

Default passwords:
SCOTT/TIGER, ADAMS/WOOD, JONES/STEEL, CLARK/CLOTH and BLAKE/PAPER.

10G onwards, by default the above users are disabled. The "emp" table is in scott's shema. To enable user scot;

  01. sqlplus
   SQL> connect sys/oracle as sysdba;
   Connected.
   SQL> alter user scott account unlock;
   User altered.

Now exit the SQL* plus command prompt and launch it once again with scott/tiger.
It will say password expired and you may have to provide new password.