新特性：CDB/PDB的维护命令：同一CDB中使用克隆PDB

本文使用的是asm，不适用于文件系统，克隆前最好将PDB1_WHS修改为readonly状态，我这里是测试环境，就不改了。

SQL> show pdbs

    CON_ID CON_NAME                       OPEN MODE  RESTRICTED
---------- ------------------------------ ---------- ----------
         2 PDB$SEED                       READ ONLY  NO
         3 PDB1_WHS                       READ WRITE NO
SQL> create pluggable database PDB2_WHS from PDB1_WHS;

Pluggable database created.

SQL> show pdbs

    CON_ID CON_NAME                       OPEN MODE  RESTRICTED
---------- ------------------------------ ---------- ----------
         2 PDB$SEED                       READ ONLY  NO
         3 PDB1_WHS                       READ WRITE NO
         4 PDB2_WHS                       MOUNTED
SQL> alter pluggable database PDB2_WHS open;

Pluggable database altered.