Check user is login with OS/Database authentication in Oracle

Following command will help to check the authentication of the connected session:

SQL> conn hr@pdb1
Enter password:
Connected.
SQL> SELECT SYS_CONTEXT('USERENV','AUTHENTICATION_TYPE') "SESSION_USER" from dual;

SESSION_USER
------------------------
DATABASE


SQL> conn / as sysdba
Connected.


SQL> SELECT SYS_CONTEXT('USERENV','AUTHENTICATION_TYPE') "SESSION_USER" from dual;

SESSION_USER
------------------
OS

AUTHENTICATION_TYPE:
DATABASE: Username/password authentication.
OS: Operating system external user authentication.
NETWORK: Network protocol authentication.
PROXY: OCI proxy connection authentication.