os: centos 7.4
db: oracle 18c(18.3)

pdb 的優勢之一就是 unplug、plug，本篇blog介紹下 pdb 的 unplug。

以 pdbdongg 為例，進行 unplug 操作。

unplug pdb

必須先 close，然後再 unplug。
需要再 cdb$root 下操作

$ sqlplus / as sysdba;

SQL> show con_name;

CON_NAME
------------------------------
CDB$ROOT

SQL> show pdbs;

    CON_ID CON_NAME			  OPEN MODE  RESTRICTED
---------- ------------------------------ ---------- ----------
	 2 PDB$SEED			  READ ONLY  NO
	 3 PDBPEIYB			  READ WRITE NO
	 4 PDBSHENZ			  READ WRITE NO
	 5 PDBGUANGZ			  READ WRITE NO
	 6 PDBDONGG			  READ WRITE NO

SQL> alter pluggable database PDBDONGG close immediate;

SQL> alter pluggable database PDBDONGG unplug into '/u01/app/oracle/unplug_pdb/PDBDONGG.xml';

SQL> show pdbs;

    CON_ID CON_NAME			  OPEN MODE  RESTRICTED
---------- ------------------------------ ---------- ----------
	 2 PDB$SEED			  READ ONLY  NO
	 3 PDBPEIYB			  READ WRITE NO
	 4 PDBSHENZ			  READ WRITE NO
	 5 PDBGUANGZ			  READ WRITE NO
	 6 PDBDONGG			  MOUNTED	 
 

有興趣，可以分析下 PDBDONGG.xml 檔案，記錄了很多重要的描述性資訊。

drop pdb

close，unplug 之後就可以 drop了，感覺和U盤的使用規則一致，也符合人的認知思維。
drop 操作也可以同時刪除資料檔案，比較威猛，慎用。
需要再 cdb$root 下操作

SQL> show pdbs;

    CON_ID CON_NAME			  OPEN MODE  RESTRICTED
---------- ------------------------------ ---------- ----------
	 2 PDB$SEED			  READ ONLY  NO
	 3 PDBPEIYB			  READ WRITE NO
	 4 PDBSHENZ			  READ WRITE NO
	 5 PDBGUANGZ			  READ WRITE NO
	 6 PDBDONGG			  MOUNTED
SQL> 
SQL> drop pluggable database PDBDONGG keep datafiles;

SQL> 
SQL> show pdbs;

    CON_ID CON_NAME			  OPEN MODE  RESTRICTED
---------- ------------------------------ ---------- ----------
	 2 PDB$SEED			  READ ONLY  NO
	 3 PDBPEIYB			  READ WRITE NO
	 4 PDBSHENZ			  READ WRITE NO
	 5 PDBGUANGZ			  READ WRITE NO

 

下面命令為刪除資料庫及資料庫檔案

SQL> drop pluggable database PDBDONGG including datafiles;  

plug pdb

plug pdb 需要使用之前 unplug 匯出的 xml檔案。
需要再 cdb$root 下操作

SQL> show pdbs;

    CON_ID CON_NAME			  OPEN MODE  RESTRICTED
---------- ------------------------------ ---------- ----------
	 2 PDB$SEED			  READ ONLY  NO
	 3 PDBPEIYB			  READ WRITE NO
	 4 PDBSHENZ			  READ WRITE NO
	 5 PDBGUANGZ			  READ WRITE NO
SQL> create pluggable database PDBDONGG using '/u01/app/oracle/unplug_pdb/PDBDONGG.xml' nocopy tempfile reuse;

SQL> show pdbs;

    CON_ID CON_NAME			  OPEN MODE  RESTRICTED
---------- ------------------------------ ---------- ----------
	 2 PDB$SEED			  READ ONLY  NO
	 3 PDBPEIYB			  READ WRITE NO
	 4 PDBSHENZ			  READ WRITE NO
	 5 PDBGUANGZ			  READ WRITE NO
	 6 PDBDONGG			  MOUNTED
	 
SQL> alter pluggable database PDBDONGG open;

SQL> show pdbs;

    CON_ID CON_NAME			  OPEN MODE  RESTRICTED
---------- ------------------------------ ---------- ----------
	 2 PDB$SEED			  READ ONLY  NO
	 3 PDBPEIYB			  READ WRITE NO
	 4 PDBSHENZ			  READ WRITE NO
	 5 PDBGUANGZ			  READ WRITE NO
	 6 PDBDONGG			  READ WRITE NO
 

這裡完全複用了之前的檔案，也可以修改為新的資料庫名和 新的目錄。比如

SQL> CREATE PLUGGABLE DATABASE PDBDONGG_PLUG1
USING '/u01/app/oracle/unplug_pdb/PDBDONGG.xml' 
COPY
file_name_convert=('/u01/app/oracle/oradata/ORCL/pdbdongg/',
                   '/u01/app/oracle/oradata/ORCL/pdbdongg_plug1/')  
STORAGE ( MAXSIZE UNLIMITED 
          MAX_SHARED_TEMP_SIZE UNLIMITED
		 )
TEMPFILE REUSE		 
PATH_PREFIX = '/u01/app/oracle/oradata/ORCL/pdbdongg_plug1/';

參考：
https://docs.oracle.com/en/database/oracle/oracle-database/18/sqlrf/ALTER-PLUGGABLE-DATABASE.html#GUID-A29491AD-8F0F-4E52-9D94-57FC3FF8FBC7
https://docs.oracle.com/en/database/oracle/oracle-database/18/sqlrf/CREATE-PLUGGABLE-DATABASE.html#GUID-F2DBA8DD-EEA8-4BB7-A07F-78DC04DB1FFC
https://docs.oracle.com/en/database/oracle/oracle-database/18/sqlrf/DROP-PLUGGABLE-DATABASE.html#GUID-4A663783-E184-417A-8BE1-703E1CDBA30B