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Oracle 12C引入了CDB与PDB的新特性,在ORACLE 12C数据库引入的多租用户环境(Multitenant Environment)中,允许一个数据库容器(CDB)承载多个可插拔数据库(PDB)。CDB全称为Container Database,中文翻译为数据库容器,PDB全称为Pluggable Database,即可
Oracle 12C引入了CDB与PDB的新特性,在ORACLE 12C数据库引入的多租用户环境(Multitenant Environment)中,允许一个数据库容器(CDB)承载多个可插拔数据库(PDB)。CDB全称为Container Database,中文翻译为数据库容器,PDB全称为Pluggable Database,即可插拔数据库。在ORACLE 12C之前,实例与数据库是一对一或多对一关系(RAC):即一个实例只能与一个数据库相关联,数据库可以被多个实例所加载。而实例与数据库不可能是一对多的关系。当进入ORACLE 12C后,实例与数据库可以是一对多的关系。下面是官方文档关于CDB与PDB的关系图。
其实大家如果对SQL SERVER比较熟悉的话,这种CDB与PDB是不是感觉和SQL SERVER的单实例多数据库架构是一回事呢。像PDB$SEED可以看成是master、msdb等系统数据库,PDBS可以看成用户创建的数据库。而可插拔的概念与SQL SERVER中的用户数据库的分离、附加其实就是那么一回事。看来ORACLE也“抄袭”了一把SQL SERVER的概念,只是改头换面的包装了一番。
CDB组件(Components of a CDB)
一个CDB数据库容器包含了下面一些组件:
ROOT组件
ROOT又叫CDB$ROOT, 存储着ORACLE提供的元数据和Common User,元数据的一个例子是ORACLE提供的PL/SQL包的源代码,Common User 是指在每个容器中都存在的用户。
SEED组件
Seed又叫PDB$SEED,这个是你创建PDBS数据库的模板,你不能在Seed中添加或修改一个对象。一个CDB中有且只能有一个Seed. 这个感念,个人感觉非常类似SQL SERVER中的model数据库。
PDBS
CDB中可以有一个或多个PDBS,PDBS向后兼容,可以像以前在数据库中那样操作PDBS,这里指大多数常规操作。
这些组件中的每一个都可以被称为一个容器。因此,ROOT(根)是一个容器,Seed(种子)是一个容器,每个PDB是一个容器。每个容器在CDB中都有一个独一无二的的ID和名称。
1)连接到CDB数据库
连接到CDB数据库容器非常简单,跟以前连接数据库是一样的
<span>[</span><span>oracle@get-orasvr02 ~</span><span>]</span>$ sqlplus <span>/</span> <span>as</span><span> sysdba SQL</span><span>*</span>Plus: Release <span><strong>12.1</strong></span>.<span><strong>0.1</strong></span>.<span><strong>0</strong></span> Production <span>on</span> Sun Oct <span><strong>20</strong></span> <span><strong>23</strong></span>:<span><strong>41</strong></span>:<span><strong>36</strong></span> <span><strong>2013</strong></span><span> Copyright (c) </span><span><strong>1982</strong></span>, <span><strong>2013</strong></span>, Oracle. <span>All</span><span> rights reserved. Connected </span><span>to</span><span> an idle instance. SQL</span><span>></span> <span>[</span><span>oracle@get-orasvr02 ~</span><span>]</span>$ sqlplus sys<span>/</span>password <span>as</span><span> sysdba SQL</span><span>*</span>Plus: Release <span><strong>12.1</strong></span>.<span><strong>0.1</strong></span>.<span><strong>0</strong></span> Production <span>on</span> Sun Oct <span><strong>20</strong></span> <span><strong>23</strong></span>:<span><strong>43</strong></span>:<span><strong>17</strong></span> <span><strong>2013</strong></span><span> Copyright (c) </span><span><strong>1982</strong></span>, <span><strong>2013</strong></span>, Oracle. <span>All</span><span> rights reserved. Connected </span><span>to</span><span> an idle instance. SQL</span><span>></span>
2)查看数据库是否为CDB
SQL<span>></span> <span>select</span> name, decode(cdb, <span>'</span><span>YES</span><span>'</span>, <span>'</span><span>Multitenant Option enabled</span><span>'</span>, <span>'</span><span>Regular 12c Database: </span><span>'</span>) "Multitenant <span>Option</span>" , open_mode, con_id <span>from</span> v$<span>database</span><span>; NAME Multitenant </span><span>Option</span><span> OPEN_MODE CON_ID </span><span>--</span><span>------- ----------------------------- -------------------- ----------</span> <span> EPPS Multitenant </span><span>Option</span> enabled <span>READ</span> WRITE <span><strong>0</strong></span>
YES表示该数据库是CDB,如果是NO表示是NO-CDB(普通数据库)
3)查看当前容器(Container)
3.1
SQL<span>></span><span> show con_name CON_NAME </span><span>--</span><span>----------------------------</span> <span> CDB$ROOT SQL</span><span>></span> <span><strong>3.2</strong></span><span> SQL</span><span>></span> <span>select</span> sys_context(<span>'</span><span>userenv</span><span>'</span>, <span>'</span><span>con_name</span><span>'</span>) "Container DB" <span>from</span><span> dual; Container DB </span><span>--</span><span>--------------------------------------------------</span> <span> CDB$ROOT SQL</span><span>></span>
4)查看CDB容器中的PDBS信息
查看CDB中有多少个pluggable database
SQL<span>></span> <span>select</span> con_id, dbid, guid, name , open_mode <span>from</span><span> v$pdbs; CON_ID DBID GUID NAME OPEN_MODE </span><span>--</span><span>-------- ---------- -------------------------------- ------------------------------ ----------</span> <span><strong>2</strong></span> <span><strong>4071321146</strong></span> E89E8DA2866E3157E043DE07A8C09238 PDB$SEED <span>READ</span> <span>ONLY</span> <span><strong>3</strong></span> <span><strong>1930201447</strong></span><span> E89E9418B882350CE043DE07A8C092B6 PDBEPPS MOUNTED SQL</span><span>></span>
5)启动PDB数据库
方式1:
SQL<span>></span> <span>alter</span> pluggable <span>database</span> PDBEPPS <span>open</span><span>; Pluggable </span><span>database</span><span> altered. SQL</span><span>></span> <span>select</span> con_id, dbid, guid, name , open_mode <span>from</span><span> v$pdbs; CON_ID DBID GUID NAME OPEN_MODE </span><span>--</span><span>-------- ---------- -------------------------------- ------------------------------ ----------</span> <span><strong>2</strong></span> <span><strong>4071321146</strong></span> E89E8DA2866E3157E043DE07A8C09238 PDB$SEED <span>READ</span> <span>ONLY</span> <span><strong>3</strong></span> <span><strong>1930201447</strong></span> E89E9418B882350CE043DE07A8C092B6 PDBEPPS <span>READ</span> WRITE
方式2:
SQL<span>></span> <span>alter</span> session <span>set</span> container<span>=</span><span>PDBEPPS; Session altered. SQL</span><span>></span><span> startup Pluggable </span><span>Database</span><span> opened. SQL</span><span>></span>
6)关闭PDB数据库
SQL> alter pluggable database PDBEPPS close;
Pluggable database altered.
SQL> select con_id, dbid, guid, name , open_mode from v$pdbs;
CON_ID DBID GUID NAME OPEN_MODE
---------- ---------- -------------------------------- ------------------------------ ----------
2 4071321146 E89E8DA2866E3157E043DE07A8C09238 PDB$SEED READ ONLY
3 1930201447 E89E9418B882350CE043DE07A8C092B6 PDBEPPS MOUNTED
SQL>
7)在容器间切换
SQL> alter session set container=PDBEPPS;
Session altered.
SQL> show con_name;
CON_NAME
------------------------------
PDBEPPS
SQL>
SQL> alter session set container=CDB$ROOT;
Session altered.
SQL> show con_name;
CON_NAME
------------------------------
CDB$ROOT
参考资料:
http://docs.oracle.com/cd/E16655_01/server.121/e17636/cdb_intro.htm
http://www.orasos.com/4445.html
http://www.oracle-base.com/articles/12c/multitenant-connecting-to-cdb-and-pdb-12cr1.php
http://www.orasos.com/4445.html