Quering v$ views

Only database created using DBCA will be listed in the /etc/oratab file, but not the manually created databases.

root> ORACLE_SID = ssss --->exporting the database id

root> sqlplus / as sysdba

SQL> startup

SQL> select name,open_mode,log_mode from v$database;

SQL> select instance_name,status from v$instance;

SQL> select name from v$tablespace;

SQL> select name from v$datafile;