SQL> select instance_name from v$instance

SQL> select instance_name from v$instance;

INSTANCE_NAME
----------------
orates05

SQL> select name from v$database;

NAME
---------
ORATES05

SQL> show parameter db_name

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
db_name                              string      orates05
SQL>
SQL>
SQL> show parameter db_domain;

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
db_domain                            string
SQL> show parameter instance_name;

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
instance_name                        string      orates05
SQL> show parameter service_names;

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
service_names                        string      orates05