First Scope of 12c Database

https://localhost:5500/em
-- with Em Express Login issues:switch to CDB$ROOT, run exec dbms_xdb_config.setglobalportenabled(TRUE);
--check https port
--common user need em_express_basic or em_empress_all role

set oracle_sid=cdb
sqlplus sys as sysdba
alter pluggable database pdb1 open;

select name, cdb,con_id from v$database;
select instance_name, status,con_id from v$instance;
select dbms_xdb_config.getHttpsPort() from dual;
select con_id, name, open_mode from v$pdbs;

--swtich to different pdb
ALTER SESSION SET CONTAINER=pdb1;
show con_name
show parameter dispatchers

--switch back to cdb
Alter session set container=CDB$ROOT;