To start Oracle Enterprise Manager Database Express (EM Express) for a pluggable database (PDB), use the EM Express URL provided by Database Configuration Assistant (DBCA) when it configured the PDB. That URL includes the HTTPS port number for the PDB.
alter session set container=PDB1; select dbms_xdb_config.gethttpsport() from dual;
If a port number is not returned by this statement, then you must manually configure an HTTPS port for this PDB, as described in "Configuring the HTTPS Port for EM Express."
When connected to a PDB, EM Express displays data and enables actions that apply to the PDB only.
Managing PDBs with EM Express for more information about using EM Express to manage the PDBs in a multitenant container database (CDB)
Oracle Database Administrator's Guide for information about switching to a container using the ALTER SESSION statement
Oracle Database PL/SQL Packages and Types Reference for more information on the