SQL> select name,open_mode from v$pdbs; NAME OPEN_MODE ------------------------------ ---------- PDB$SEED READ ONLY PDB1 MOUNTED PDB2 MOUNTED SQL> alter pluggable database all open; Pluggable database altered. SQL> select name,open_mode from v$pdbs; NAME OPEN_MODE ------------------------------ ---------- PDB$SEED READ ONLY PDB1 READ WRITE PDB2 READ WRITE SQL> alter pluggable database all close; Pluggable database altered. SQL> select name,open_mode from v$pdbs; NAME OPEN_MODE ------------------------------ ---------- PDB$SEED READ ONLY PDB1 MOUNTED PDB2 MOUNTED SQL>