====== Switch to a pluggable db (Oracle 12) ======
After you are connected with sqlplus to a container database (which is happening by default), run the connect command inside your sqlplus session.
conn SYS@PMJ as SYSDBA
Then you'll be required to enter the SYS password. \\
* If you use a non dba user, don't specify 'as SYSDBA' clause.
* Here PMJ is the name of the pluggable database.
Another way to switch to a PDB is to change the container:
alter session set container=PMJ;
To go back to the CDB container:
alter session set container=CDB$ROOT;
====== Connect directly to a pluggable db ======
sqlplus /nolog
connect SNT@PMJ