默认情况下，在CDB 启动的时候，all 的PDB 都是mount状态，也没有默认的机制，在CDB启动时自动启动PDB。

这里我们通过触发器的方式实现。

CREATE OR REPLACE TRIGGER open_pdbs
AFTER STARTUP ON DATABASE
BEGIN
EXECUTE IMMEDIATE 'ALTER PLUGGABLE DATABASE ALL OPEN';
END open_pdbs;
/

实验过程如下：

SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup
ORACLE instance started.Total System Global Area 1560281088 bytes
Fixed Size                  2924784 bytes
Variable Size             956305168 bytes
Database Buffers          587202560 bytes
Redo Buffers               13848576 bytes
Database mounted.
Database opened.
SQL> show pdbsCON_ID CON_NAME                       OPEN MODE  RESTRICTED
---------- ------------------------------ ---------- ----------2 PDB$SEED                       READ ONLY  NO3 PDB1                           MOUNTED
SQL> CREATE OR REPLACE TRIGGER open_pdbs2  AFTER STARTUP ON DATABASE3  BEGIN4  EXECUTE IMMEDIATE 'ALTER PLUGGABLE DATABASE ALL OPEN';5  END open_pdbs;6  /Trigger created.

SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup
ORACLE instance started.Total System Global Area 1560281088 bytes
Fixed Size                  2924784 bytes
Variable Size             956305168 bytes
Database Buffers          587202560 bytes
Redo Buffers               13848576 bytes
Database mounted.
Database opened.
SQL> show con_nameCON_NAME
------------------------------
CDB$ROOT
SQL> show pdbsCON_ID CON_NAME                       OPEN MODE  RESTRICTED
---------- ------------------------------ ---------- ----------2 PDB$SEED                       READ ONLY  NO3 PDB1                           READ WRITE NO
SQL>