Find name of Oracle Database

Check database name from v$database view

SQL> select name from V$database;

NAME
---------
XE

Check parameter db_name from SQLPLUS

SQL> show parameter db_name

NAME       TYPE       VALUE
---------- ---------- -----------
db_name    string     XE

Check if you are using Container database , which database you are connected currently

SQL> show con_name

CON_NAME
------------------------------
PDB1