How to check if connected to Oracle Pluggable Database (PDB)

 To know if you are connected to a Pluggable Database ( PDB) which is part of Container Database(CDB)

Execute below SQL script.

SELECT DECODE (SYS_CONTEXT ('Userenv', 'CDB_NAME')

                                         ,null,'NO','YES'),

                                  Sys_Context('Userenv', 'CON_ID'),

                                  Sys_Context('Userenv', 'CON_NAME')

                          From dual;

If connected to PDB you will get first column value as YES , a non zero number for second column and PDB Name in third column

If connected to a normal database (non CDB/PDB) you will get first column value as NO, zero for second column and Database Name in third column.