在ORACLE 12C中参数文件只是记录了cdb的参数信息,没有记录任何的pdb的信息,那ORACLE是如何管理使得各个pdb有自己的参数,这里通过试验的出来ORACLE 12C CDB环境中是通过参数文件结合PDB_SPFILE$来实现参数管理
数据库版本

SQL> select * from v$version;
BANNER                                                                               CON_ID
-------------------------------------------------------------------------------- ----------
Oracle Database 12c Enterprise Edition Release 12.1.0.1.0 - 64bit Production              0
PL/SQL Release 12.1.0.1.0 - Production                                                    0
CORE    12.1.0.1.0      Production                                                        0
TNS for Linux: Version 12.1.0.1.0 - Production                                            0
NLSRTL Version 12.1.0.1.0 - Production                                                    0

pdb信息

SQL>  select PDB_NAME,CON_UID,pdb_id,status from dba_pdbs;
PDB_NAME      CON_UID     PDB_ID STATUS
---------- ---------- ---------- -------------
PDB1       3313918585          3 NORMAL
PDB$SEED   4048821679          2 NORMAL
PDB2       3872456618          4 NORMAL
SQL> select con_id,dbid,NAME,OPEN_MODE from v$pdbs;
    CON_ID       DBID NAME                           OPEN_MODE
---------- ---------- ------------------------------ ----------
         2 4048821679 PDB$SEED                       READ ONLY
         3 3313918585 PDB1                           READ WRITE
         4 3872456618 PDB2                           MOUNTED

CDB$ROOT中修改参数

--指定container=all
SQL> show con_name
CON_NAME
------------------------------
CDB$ROOT
SQL> alter system set open_cursors=500 container=all;
System altered.
SQL> show parameter open_cursors;
NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
open_cursors                         integer     500
SQL> alter session set container=pdb1;
Session altered.
SQL> show con_name
CON_NAME
------------------------------
PDB1
SQL> show parameter open_cursors;
NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
open_cursors                         integer     500
--在CDB$ROOT中修改不指定container参数表示全部pdb生效
SQL> alter session set container=CDB$ROOT;
Session altered.
SQL> alter system set open_cursors=100;
System altered.
SQL>  show parameter open_cursors;
NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
open_cursors                         integer     100
SQL> alter session set container=pdb1;
Session altered.
SQL> show parameter open_cursors;
NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
open_cursors                         integer     100
--指定container=current
SQL> alter system set open_cursors=120 container=current;
System altered.
SQL> show parameter open_cursors;
NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
open_cursors                         integer     120
SQL> alter session set container=pdb2 ;
Session altered.
SQL> show parameter open_cursors;
NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
open_cursors                         integer     120

这里可以看出来,在ROOT中修改参数,默认情况和指定container=all/current均是所有open的pdb都生效.
这里有个疑问ORACLE的参数文件只是记录的cdb的sid的参数,并未记录各个pdb的参数,那是如何实现cdb中各个pdb参数不一致的呢？继续分析

修改pdb参数做10046

SQL> show con_name;
CON_NAME
------------------------------
PDB1
SQL> oradebug setmypid
Statement processed.
SQL> oradebug EVENT 10046 TRACE NAME CONTEXT FOREVER, LEVEL 12
Statement processed.
SQL> oradebug TRACEFILE_NAME
/u01/app/oracle/diag/rdbms/cdb/cdb/trace/cdb_ora_18377.trc
SQL> alter system set sessions=100;
System altered.
SQL> oradebug EVENT 10046 trace name context off
Statement processed.
--继续修改pdb参数
SQL> alter session set container=pdb1;
Session altered.
SQL>  oradebug setmypid
Statement processed.
SQL> oradebug EVENT 10046 TRACE NAME CONTEXT FOREVER, LEVEL 12
Statement processed.
SQL>  oradebug TRACEFILE_NAME
/u01/app/oracle/diag/rdbms/cdb/cdb/trace/cdb_ora_20275.trc
SQL> alter system set sessions=101;
System altered.
SQL> oradebug EVENT 10046 trace name context off
Statement processed.

分析trace文件

--第一次修改pdb参数值
insert into pdb_spfile$(db_uniq_name, pdb_uid, sid, name, value$, comment$)  values(:1,:2,:3,:4,:5,:6)
END OF STMT
PARSE #140085118752824:c=3999,e=3397,p=0,cr=0,cu=0,mis=1,r=0,dep=1,og=4,plh=0,tim=99767937623
BINDS #140085118752824:
 Bind#0
  oacdty=01 mxl=32(03) mxlc=00 mal=00 scl=00 pre=00
  oacflg=10 fl2=0001 frm=01 csi=852 siz=32 off=0
  kxsbbbfp=7fffcfaa5842  bln=32  avl=03  flg=09
  value="cdb"
 Bind#1
  oacdty=02 mxl=22(22) mxlc=00 mal=00 scl=00 pre=00
  oacflg=00 fl2=1000001 frm=00 csi=00 siz=24 off=0
  kxsbbbfp=7f681bbb2170  bln=22  avl=06  flg=05
  value=3313918585
 Bind#2
  oacdty=01 mxl=32(01) mxlc=00 mal=00 scl=00 pre=00
  oacflg=10 fl2=0001 frm=01 csi=852 siz=32 off=0
  kxsbbbfp=7fffcfaa46f8  bln=32  avl=01  flg=09
  value="*"
 Bind#3
  oacdty=01 mxl=32(08) mxlc=00 mal=00 scl=00 pre=00
  oacflg=10 fl2=0001 frm=01 csi=852 siz=32 off=0
  kxsbbbfp=0bc220d8  bln=32  avl=08  flg=09
  value="sessions"
 Bind#4
  oacdty=01 mxl=32(03) mxlc=00 mal=00 scl=00 pre=00
  oacflg=10 fl2=0001 frm=01 csi=852 siz=32 off=0
  kxsbbbfp=7fffcfaa474c  bln=32  avl=03  flg=09
  value="100"
 Bind#5
  oacdty=01 mxl=32(00) mxlc=00 mal=00 scl=00 pre=00
  oacflg=10 fl2=0001 frm=01 csi=852 siz=32 off=0
  kxsbbbfp=00000000  bln=32  avl=00  flg=09
--第二次修改pdb参数值(相同参数)
update pdb_spfile$ set value$=:5, comment$=:6  where name=:1 and pdb_uid=:2 and db_uniq_name=:3 and sid=:4
BINDS #140603847818408:
 Bind#0
  oacdty=01 mxl=32(03) mxlc=00 mal=00 scl=00 pre=00
  oacflg=10 fl2=0001 frm=01 csi=852 siz=32 off=0
  kxsbbbfp=7ffff6477dcc  bln=32  avl=03  flg=09
  value="101"
 Bind#1
  oacdty=01 mxl=32(00) mxlc=00 mal=00 scl=00 pre=00
  oacflg=10 fl2=0001 frm=01 csi=852 siz=32 off=0
  kxsbbbfp=00000000  bln=32  avl=00  flg=09
 Bind#2
  oacdty=01 mxl=32(08) mxlc=00 mal=00 scl=00 pre=00
  oacflg=10 fl2=0001 frm=01 csi=852 siz=32 off=0
  kxsbbbfp=0bc220d8  bln=32  avl=08  flg=09
  value="sessions"
 Bind#3
  oacdty=02 mxl=22(22) mxlc=00 mal=00 scl=00 pre=00
  oacflg=00 fl2=1000001 frm=00 csi=00 siz=24 off=0
  kxsbbbfp=7fe0e2638320  bln=22  avl=06  flg=05
  value=3313918585
 Bind#4
  oacdty=01 mxl=32(03) mxlc=00 mal=00 scl=00 pre=00
  oacflg=10 fl2=0001 frm=01 csi=852 siz=32 off=0
  kxsbbbfp=7ffff6478ec2  bln=32  avl=03  flg=09
  value="cdb"
 Bind#5
  oacdty=01 mxl=32(01) mxlc=00 mal=00 scl=00 pre=00
  oacflg=10 fl2=0001 frm=01 csi=852 siz=32 off=0
  kxsbbbfp=7ffff6477d78  bln=32  avl=01  flg=09
  value="*"

通过这里我们发现在独立修改pdb参数之时,其本质是在pdb_spfile$基表中插入或者修改相关记录(第一次修改插入,后续修改是更新)

关于pdb_spfile$基表分析

SQL> SHOW CON_NAME;
CON_NAME
------------------------------
CDB$ROOT
SQL> COL OWNER FOR A10
SQL> select con_id,owner,object_type from cdb_objects where object_name='PDB_SPFILE$';
    CON_ID OWNER      OBJECT_TYPE
---------- ---------- -----------------------
         2 SYS        TABLE
         1 SYS        TABLE
         3 SYS        TABLE
SQL> COL DB_UNIQ_NAME FOR A10
SQL> COL NAME FOR A15
SQL> COL VALUE$ FOR A10
SQL> SELECT DB_UNIQ_NAME,PDB_UID,NAME,VALUE$ FROM PDB_SPFILE$;
DB_UNIQ_NA    PDB_UID NAME            VALUE$
---------- ---------- --------------- ----------
cdb        3313918585 sessions        101
SQL> ALTER SESSION SET CONTAINER=pdb1;
Session altered.
SQL>  SELECT DB_UNIQ_NAME,PDB_UID,NAME,VALUE$ FROM PDB_SPFILE$;
no rows selected

证明pdb中不同于root的参数是记录在root的PDB_SPFILE$基表中.
整个CDB的工作原理是如果在PDB_SPFILE$中无相关参数记录,则继承cdb的参数文件中值,如果PDB_SPFILE$中有记录则使用该值覆盖cdb参数文件值.

删除PDB_SPFILE$验证

SQL> SHOW CON_NAME;
CON_NAME
------------------------------
CDB$ROOT
SQL> show parameter open_cursors;
NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
open_cursors                         integer     100
SQL>  select con_id,dbid,NAME,OPEN_MODE from v$pdbs;
    CON_ID       DBID NAME                           OPEN_MODE
---------- ---------- ------------------------------ ----------
         2 4048821679 PDB$SEED                       READ ONLY
         3 3313918585 PDB1                           MOUNTED
         4 3872456618 PDB2                           READ WRITE
SQL> alter session set container=pdb2;
Session altered.
SQL> show parameter open_cursors;
NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
open_cursors                         integer     100
SQL> alter system set open_cursors=110;
System altered.
SQL> show parameter open_cursors;
NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
open_cursors                         integer     110
SQL> conn / as sysdba
Connected.
SQL> select value$ from pdb_spfile$ where name='open_cursors';
VALUE$
--------------------------------------------------------------------------------
110
SQL> delete from  pdb_spfile$ where name='open_cursors';
1 row deleted.
SQL> commit;
Commit complete.
SQL> startup
ORACLE instance started.
Total System Global Area  597098496 bytes
Fixed Size                  2291072 bytes
Variable Size             272632448 bytes
Database Buffers          314572800 bytes
Redo Buffers                7602176 bytes
Database mounted.
Database opened.
SQL> select value$ from pdb_spfile$ where name='open_cursors';
no rows selected
SQL> show parameter open_cursors;
NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
open_cursors                         integer     100
SQL> alter session set container=pdb2 ;
Session altered.
SQL> alter database open;
Database altered.
SQL>  show parameter open_cursors;
NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
open_cursors                         integer     100

删除PDB_SPFILE$中相关记录,pdb的参数值会自动继续继承cdb中参数值
总结说明:通过上述的一些列试验证明cdb中参数关系,在cdb中修改,会默认所有pdb均自动继承;如果在pdb中修改值会覆盖cdb参数,而且只对当前pdb生效,并记录在PDB_SPFILE$

在ORACLE 12C中引入了CDB和PDB的概念,实现了ORACLE数据库的可插拔,在一个CDB数据库中,有多个PDB,而每一个PDB又可以理解为一个独立的传统ORACLE 数据库,那为了能够通过一个sql查询获得整个CDB数据库的信息,ORALCE 引入了CDB_*开头的视图,该视图就是在传统的DBA_*视图基础之上增加了CON_ID,用来区分不同的PDB,从而实现了一个简单sql查询在有足够权限的情况下,可以查询所有PDB中信息
ORACLE 12C版本

SQL> select * from v$version;
BANNER                                                                               CON_ID
-------------------------------------------------------------------------------- ----------
Oracle Database 12c Enterprise Edition Release 12.1.0.1.0 - 64bit Production              0
PL/SQL Release 12.1.0.1.0 - Production                                                    0
CORE    12.1.0.1.0      Production                                                        0
TNS for Linux: Version 12.1.0.1.0 - Production                                            0
NLSRTL Version 12.1.0.1.0 - Production                                                    0

确定是否是CDB

SQL> SELECT CDB FROM V$DATABASE;
CDB
---
YES

YES表示该数据库是CDB,如果是NO表示是NO-CDB(普通数据库)

CDB中各容器信息

SQL> COLUMN NAME FORMAT A8
SQL> SELECT NAME, CON_ID, DBID, CON_UID, GUID FROM V$CONTAINERS ORDER BY CON_ID;
NAME         CON_ID       DBID    CON_UID GUID
-------- ---------- ---------- ---------- --------------------------------
CDB$ROOT          1 1922813718          1 DB85A3D39F8E7703E0431CAAE80A8C44
PDB$SEED          2 4048821679 4048821679 D49B80694E4A449BE0430100007F906F
PDB1              3 3313918585 3313918585 D49BF37938FB4C10E0430100007F6CBD
PDB2              4 3872456618 3872456618 D49BFA33332F4C3EE0430100007FA059
SQL> select CON_NAME_TO_ID('PDB1') FROM DUAL;
CON_NAME_TO_ID('PDB1')
----------------------
                     3
SQL> SELECT CON_DBID_TO_ID(3313918585) FROM DUAL;
CON_DBID_TO_ID(3313918585)
--------------------------
                         3
SQL> SELECT CON_UID_TO_ID(3313918585) FROM DUAL;
CON_UID_TO_ID(3313918585)
-------------------------
                        3

PDB部分信息

SQL> COLUMN PDB_NAME FORMAT A15
SQL> SELECT PDB_ID, PDB_NAME, STATUS FROM DBA_PDBS ORDER BY PDB_ID;
    PDB_ID PDB_NAME        STATUS
---------- --------------- -------------
         2 PDB$SEED        NORMAL
         3 PDB1            NORMAL
         4 PDB2            NORMAL
SQL> COLUMN NAME FORMAT A15
SQL> COLUMN RESTRICTED FORMAT A10
SQL> COLUMN OPEN_TIME FORMAT A30
SQL> SELECT NAME, OPEN_MODE, RESTRICTED, OPEN_TIME FROM V$PDBS;
NAME            OPEN_MODE  RESTRICTED OPEN_TIME
--------------- ---------- ---------- ------------------------------
PDB$SEED        READ ONLY  NO         12-MAY-13 08.51.53.177 AM
PDB1            READ WRITE NO         12-MAY-13 09.35.48.646 AM
PDB2            MOUNTED               12-MAY-13 08.56.59.859 AM

CDB中查询对象信息

SQL> COLUMN PDB_NAME FORMAT A15
SQL> COLUMN OWNER FORMAT A15
SQL> COLUMN TABLE_NAME FORMAT A30
SQL> SELECT p.PDB_ID, p.PDB_NAME, t.OWNER, t.TABLE_NAME
  2  FROM DBA_PDBS p, CDB_TABLES t
  3  WHERE p.PDB_ID > 2
  4  AND T.TABLE_NAME='COL$'
  5  AND p.PDB_ID = t.CON_ID
  6  ORDER BY p.PDB_ID;
    PDB_ID PDB_NAME        OWNER           TABLE_NAME
---------- --------------- --------------- ------------------------------
         3 PDB1            SYS             COL$
         4 PDB2            SYS             COL$

查询在CDB中的PDB数据/临时文件信息

SQL> COLUMN PDB_ID FORMAT 999
SQL> COLUMN PDB_NAME FORMAT A8
SQL> COLUMN FILE_ID FORMAT 9999
SQL> COLUMN TABLESPACE_NAME FORMAT A10
SQL> COLUMN FILE_NAME FORMAT A45
SQL> SELECT p.PDB_ID, p.PDB_NAME, d.FILE_ID, d.TABLESPACE_NAME, d.FILE_NAME
  2  FROM DBA_PDBS p, CDB_DATA_FILES d
  3  WHERE p.PDB_ID = d.CON_ID
  4  ORDER BY p.PDB_ID;
PDB_ID PDB_NAME FILE_ID TABLESPACE FILE_NAME
------ -------- ------- ---------- ---------------------------------------------
     2 PDB$SEED       5 SYSTEM     +DATA/pdb$seed_system01.dbf
     2 PDB$SEED       7 SYSAUX     +DATA/pdb$seed_sysaux01.dbf
     3 PDB1           9 SYSAUX     +DATA/pdb1_pdb$seed_sysaux01.dbf
     3 PDB1          10 USERS      +DATA/cdb/pdb1_users01.dbf
     3 PDB1           8 SYSTEM     +DATA/pdb1_pdb$seed_system01.dbf
     4 PDB2          13 USERS      +DATA/cdb/pdb2_users01.dbf
     4 PDB2          12 SYSAUX     +DATA/pdb2_pdb$seed_sysaux01.dbf
     4 PDB2          11 SYSTEM     +DATA/pdb2_pdb$seed_system01.dbf
8 rows selected.
SQL> COLUMN CON_ID FORMAT 999
SQL> COLUMN FILE_ID FORMAT 9999
SQL> COLUMN TABLESPACE_NAME FORMAT A15
SQL> COLUMN FILE_NAME FORMAT A45
SQL> SELECT CON_ID, FILE_ID, TABLESPACE_NAME, FILE_NAME
  2  FROM CDB_TEMP_FILES
  3  ORDER BY CON_ID;
CON_ID FILE_ID TABLESPACE_NAME FILE_NAME
------ ------- --------------- ---------------------------------------------
     1       1 TEMP            +DATA/cdb/temp01.dbf
     2       2 TEMP            +DATA/pdbseed_temp01.dbf
     3       3 TEMP            +DATA/pdb1_temp01.dbf
     4       4 TEMP            +DATA/pdb2_temp01.dbf

查询PDB的service信息

SQL> COLUMN NETWORK_NAME FORMAT A30
SQL> COLUMN PDB FORMAT A15
SQL> COLUMN CON_ID FORMAT 999
SQL> SELECT PDB, NETWORK_NAME, CON_ID FROM CDB_SERVICES
  2  WHERE PDB IS NOT NULL AND
  3  CON_ID > 2
  4  ORDER BY PDB;
PDB             NETWORK_NAME                   CON_ID
--------------- ------------------------------ ------
PDB1            pdb1                                3
PDB2            pdb2                                4

PDB中可以修改参数

SELECT NAME FROM V$SYSTEM_PARAMETER
WHERE ISPDB_MODIFIABLE = 'TRUE'
ORDER BY NAME;

查看PDB历史信息

SQL> COLUMN DB_NAME FORMAT A10
SQL> COLUMN CON_ID FORMAT 999
SQL> COLUMN PDB_NAME FORMAT A15
SQL> COLUMN OPERATION FORMAT A16
SQL> COLUMN OP_TIMESTAMP FORMAT A10
SQL> COLUMN CLONED_FROM_PDB_NAME FORMAT A15
SQL> SELECT DB_NAME, CON_ID, PDB_NAME, OPERATION, OP_TIMESTAMP, CLONED_FROM_PDB_NAME
  2  FROM CDB_PDB_HISTORY
  3  WHERE CON_ID > 2
  4  ORDER BY CON_ID;
DB_NAME    CON_ID PDB_NAME        OPERATION        OP_TIMESTA CLONED_FROM_PDB
---------- ------ --------------- ---------------- ---------- ---------------
SEEDDATA        3 PDB$SEED        UNPLUG           29-APR-13
CDB             3 PDB1            CREATE           01-FEB-13  PDB$SEED
CDB             3 PDB$SEED        PLUG             01-FEB-13  PDB$SEED
SEEDDATA        4 PDB$SEED        UNPLUG           29-APR-13
CDB             4 PDB2            CREATE           01-FEB-13  PDB$SEED
CDB             4 PDB$SEED        PLUG             01-FEB-13  PDB$SEED
6 rows selected.

CDB和PDB是ORACLE 12C一个很亮的新特性,由于他们的引入导致传统的ORACLE数据库管理理念不少发生了改变,这里列举了部分最基本的cdb和pdb管理方式
cdb和pdb关系图

ORACLE 12C版本

SQL> select * from v$version;
BANNER                                                                               CON_ID
-------------------------------------------------------------------------------- ----------
Oracle Database 12c Enterprise Edition Release 12.1.0.1.0 - 64bit Production              0
PL/SQL Release 12.1.0.1.0 - Production                                                    0
CORE    12.1.0.1.0      Production                                                        0
TNS for Linux: Version 12.1.0.1.0 - Production                                            0
NLSRTL Version 12.1.0.1.0 - Production                                                    0

启动关闭pdb

SQL> startup
ORACLE instance started.
Total System Global Area  597098496 bytes
Fixed Size                  2291072 bytes
Variable Size             272632448 bytes
Database Buffers          314572800 bytes
Redo Buffers                7602176 bytes
Database mounted.
Database opened.
SQL> select con_id,dbid,NAME,OPEN_MODE from v$pdbs;
    CON_ID       DBID NAME                           OPEN_MODE
---------- ---------- ------------------------------ ----------
         2 4048821679 PDB$SEED                       READ ONLY
         3 3313918585 PDB1                           MOUNTED
         4 3872456618 PDB2                           MOUNTED
SQL> alter PLUGGABLE database pdb1 open;
Pluggable database altered.
SQL> select con_id,dbid,NAME,OPEN_MODE from v$pdbs;
    CON_ID       DBID NAME                           OPEN_MODE
---------- ---------- ------------------------------ ----------
         2 4048821679 PDB$SEED                       READ ONLY
         3 3313918585 PDB1                           READ WRITE
         4 3872456618 PDB2                           MOUNTED
SQL> alter PLUGGABLE database pdb1 close;
Pluggable database altered.
SQL> select con_id,dbid,NAME,OPEN_MODE from v$pdbs;
    CON_ID       DBID NAME                           OPEN_MODE
---------- ---------- ------------------------------ ----------
         2 4048821679 PDB$SEED                       READ ONLY
         3 3313918585 PDB1                           MOUNTED
         4 3872456618 PDB2                           MOUNTED
SQL> alter PLUGGABLE database all open;
Pluggable database altered.
SQL> select con_id,dbid,NAME,OPEN_MODE from v$pdbs;
    CON_ID       DBID NAME                           OPEN_MODE
---------- ---------- ------------------------------ ----------
         2 4048821679 PDB$SEED                       READ ONLY
         3 3313918585 PDB1                           READ WRITE
         4 3872456618 PDB2                           READ WRITE
SQL> alter PLUGGABLE database all close;
Pluggable database altered.
SQL> select con_id,dbid,NAME,OPEN_MODE from v$pdbs;
    CON_ID       DBID NAME                           OPEN_MODE
---------- ---------- ------------------------------ ----------
         2 4048821679 PDB$SEED                       READ ONLY
         3 3313918585 PDB1                           MOUNTED
         4 3872456618 PDB2                           MOUNTED
SQL> alter session set container=pdb1;
Session altered.
SQL> startup
Pluggable Database opened.
SQL>  select con_id,dbid,NAME,OPEN_MODE from v$pdbs;
    CON_ID       DBID NAME                           OPEN_MODE
---------- ---------- ------------------------------ ----------
         3 3313918585 PDB1                           READ WRITE

pdb的管理可以在cdb中进行也可以在pdb中进行,如果是cdb中进行,需要PLUGGABLE关键字,如果是pdb中直接和普通数据库一样

登录pdb

[oracle@xifenfei ~]$ lsnrctl status
LSNRCTL for Linux: Version 12.1.0.1.0 - Production on 12-MAY-2013 08:07:02
Copyright (c) 1991, 2013, Oracle.  All rights reserved.
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=xifenfei)(PORT=1521)))
STATUS of the LISTENER
------------------------
Alias                     LISTENER
Version                   TNSLSNR for Linux: Version 12.1.0.1.0 - Production
Start Date                11-MAY-2013 18:30:54
Uptime                    0 days 13 hr. 36 min. 8 sec
Trace Level               off
Security                  ON: Local OS Authentication
SNMP                      OFF
Listener Parameter File   /u01/app/grid/product/12.1/network/admin/listener.ora
Listener Log File         /u01/app/grid/diag/tnslsnr/xifenfei/listener/alert/log.xml
Listening Endpoints Summary...
  (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=EXTPROC1521)))
  (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=xifenfei)(PORT=1521)))
  (DESCRIPTION=(ADDRESS=(PROTOCOL=tcps)(HOST=xifenfei)(PORT=5500))
(Security=(my_wallet_directory=/u01/oracle/12.1/db_1/admin/cdb/xdb_wallet))(Presentation=HTTP)(Session=RAW))
Services Summary...
Service "+ASM" has 1 instance(s).
  Instance "+ASM", status READY, has 1 handler(s) for this service...
Service "cdb" has 1 instance(s).
  Instance "cdb", status READY, has 1 handler(s) for this service...
Service "cdbXDB" has 1 instance(s).
  Instance "cdb", status READY, has 1 handler(s) for this service...
Service "pdb1" has 1 instance(s).
  Instance "cdb", status READY, has 1 handler(s) for this service...
Service "pdb2" has 1 instance(s).
  Instance "cdb", status READY, has 1 handler(s) for this service...
The command completed successfully
[oracle@xifenfei ~]$ tnsping pdb1
TNS Ping Utility for Linux: Version 12.1.0.1.0 - Production on 12-MAY-2013 08:07:09
Copyright (c) 1997, 2013, Oracle.  All rights reserved.
Used parameter files:
Used TNSNAMES adapter to resolve the alias
Attempting to contact (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = xifenfei)
(PORT = 1521)) (CONNECT_DATA = (SERVER = DEDICATED) (SERVICE_NAME = pdb1)))
OK (20 msec)
[oracle@xifenfei ~]$ sqlplus sys/xifenfei@pdb1 as sysdba
SQL*Plus: Release 12.1.0.1.0 Production on Sun May 12 08:08:02 2013
Copyright (c) 1982, 2013, Oracle.  All rights reserved.
Connected to:
Oracle Database 12c Enterprise Edition Release 12.1.0.1.0 - 64bit Production
With the Partitioning, Automatic Storage Management, OLAP, Advanced Analytics
and Real Application Testing options
SQL> show con_name;
CON_NAME
------------------------------
PDB1
[oracle@xifenfei ~]$ sqlplus / as sysdba
SQL*Plus: Release 12.1.0.1.0 Production on Sun May 12 08:09:14 2013
Copyright (c) 1982, 2013, Oracle.  All rights reserved.
Connected to:
Oracle Database 12c Enterprise Edition Release 12.1.0.1.0 - 64bit Production
With the Partitioning, Automatic Storage Management, OLAP, Advanced Analytics
and Real Application Testing options
SQL> alter session set container=pdb1;
Session altered.
SQL> show con_name;
CON_NAME
------------------------------
PDB1

pdb可以通过alter session container进入也可以直接通过tns方式登录

创建用户

SQL> show con_name;
CON_NAME
------------------------------
CDB$ROOT
SQL> select con_id,dbid,NAME,OPEN_MODE from v$pdbs;
    CON_ID       DBID NAME                           OPEN_MODE
---------- ---------- ------------------------------ ----------
         2 4048821679 PDB$SEED                       READ ONLY
         3 3313918585 PDB1                           READ WRITE
         4 3872456618 PDB2                           MOUNTED
SQL> create user xff identified by xifenfei;
create user xff identified by xifenfei
            *
ERROR at line 1:
ORA-65096: invalid common user or role name
SQL> !oerr ora 65096
65096, 00000, "invalid common user or role name"
// *Cause:  An attempt was made to create a common user or role with a name
//          that wass not valid for common users or roles.  In addition to
//          the usual rules for user and role names, common user and role
//          names must start with C## or c## and consist only of ASCII
//          characters.
// *Action: Specify a valid common user or role name.
//
SQL> create user c##xff identified by xifenfei;
User created.
SQL> SELECT USERNAME,CON_ID,USER_ID FROM CDB_USERS WHERE USERNAME='C##XFF';
USERNAME       CON_ID    USER_ID
---------- ---------- ----------
C##XFF              1        103
C##XFF              3        104
SQL> alter session set container=pdb1;
Session altered.
SQL> show con_name
CON_NAME
------------------------------
PDB1
SQL> create user xff identified by xifenfei;
User created.
SQL> create user c##abc identified by xifenfei;
create user c##abc identified by xifenfei
            *
ERROR at line 1:
ORA-65094: invalid local user or role name

创建用户默认的是container=all,在cdb中只能创建全局用户(c##开头),会在cdb和所有的pdb中创建该用户(但是pdb中的全局用户需要另外授权才能够在pdb中访问)。在pdb中只能创建的用户为本地用户

用户授权

SQL> grant connect to c##xff;
Grant succeeded.
SQL> select GRANTEE,con_id from cdb_ROLE_PRIVS where GRANTED_ROLE='CONNECT' AND GRANTEE='C##XFF';
GRANTEE                            CON_ID
------------------------------ ----------
C##XFF                                  1
SQL> grant resource to c##xff container=all;
Grant succeeded.
SQL>  select GRANTEE,con_id from cdb_ROLE_PRIVS where GRANTED_ROLE='RESOURCE' AND  GRANTEE='C##XFF';
GRANTEE                            CON_ID
------------------------------ ----------
C##XFF                                  1
C##XFF                                  3

用户授权默认情况下是只会给当前container,在cdb中也可以指定container=all,对所有open的pdb且存在该用户都进行授权

修改参数

SQL> alter system set open_cursors=500 container=all;
System altered.
SQL> conn sys/xifenfei@pdb1 as sysdba
Connected.
SQL> show parameter open_cursors;
NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
open_cursors                         integer     500
SQL>  alter system set open_cursors=100;
 alter system set open_cursors=100
*
ERROR at line 1:
ORA-01219: database or pluggable database not open: queries allowed on fixed
tables or views only
SQL> alter database open;
Database altered.
SQL> alter system set open_cursors=100;
System altered.
SQL>  show parameter open_cursors;
NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
open_cursors                         integer     100
SQL> conn / as sysdba
Connected.
SQL> show parameter open_cursors;
NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
open_cursors                         integer     500

这里可以看到在cdb中修改,pdb会继承进去;如果在pdb中修改会覆盖pdb从cdb中继承的参数含义

在ORACLE 12C支持在sql语句中编写函数,用来实现sql语句操作需要使用函数的部分功能,该功能对于你不想在数据库中新建函数 or 你的库是read only模式下要使用新函数实现某种功能,可以通过这种方法实现,增加了ORACLE数据库灵活点

SQL> select * from v$version;
BANNER                                                                               CON_ID
-------------------------------------------------------------------------------- ----------
Oracle Database 12c Enterprise Edition Release 12.1.0.1.0 - 64bit Production              0
PL/SQL Release 12.1.0.1.0 - Production                                                    0
CORE    12.1.0.1.0      Production                                                        0
TNS for Linux: Version 12.1.0.1.0 - Production                                            0
NLSRTL Version 12.1.0.1.0 - Production                                                    0

测试过程创建一个简单函数,用来判断输入数据值是否是数字,如果是数字输出Y,如果不是输出N.
如果是12C以前的数据库,需要事先创建一个函数,然后通过select语句条用;但是在12C中直接通过一条select语句解决

SQL> with function Is_Number
  2    (x in varchar2) return varchar2 is
  3      Plsql_Num_Error exception;
  4       pragma exception_init(Plsql_Num_Error, -06502);
  5   begin
  6     if (To_Number(x) is NOT null) then
  7       return 'Y';
  8     else
  9       return '';
 10     end if;
 11   exception
 12    when Plsql_Num_Error then
 13      return 'N';
 14   end Is_Number;
 15  select is_number('www.xifenfei.com') is_num from dual;
 16  /
IS_NUM
--------------------------------------------------------------------------------
N

从oracle 12c开始,oracle 也提供了类似sql server的top,mysql的limit分页功能，在本文中分别通过TOP N和传统方法来实现分页，sql实现效果是(按照id 倒序排列，取第六条到底十条)
TOP N写法

SQL> select * from v$version;
BANNER                                                                               CON_ID
-------------------------------------------------------------------------------- ----------
Oracle Database 12c Enterprise Edition Release 12.1.0.0.2 - 64bit                         0
PL/SQL Release 12.1.0.0.2                                                                 0
CORE    12.1.0.0.2                                                                        0
TNS for Linux: Version 12.1.0.0.2                                                         0
NLSRTL Version 12.1.0.0.2                                                                 0
SQL> set autot on exp stat
SQL> SELECT id
  2  FROM t_xifenfei
  3  ORDER BY id  desc offset 5 rows FETCH next 5 ROWS ONLY;
        ID
----------
       188
       187
       186
       185
       184
Execution Plan
----------------------------------------------------------
Plan hash value: 755690401
---------------------------------------------------------------------------------------
| Id  | Operation                | Name       | Rows  | Bytes | Cost (%CPU)| Time     |
---------------------------------------------------------------------------------------
|   0 | SELECT STATEMENT         |            |   192 |  7488 |     3   (0)| 00:00:01 |
|*  1 |  VIEW                    |            |   192 |  7488 |     3   (0)| 00:00:01 |
|*  2 |   WINDOW SORT PUSHED RANK|            |   192 |   768 |     3   (0)| 00:00:01 |
|   3 |    TABLE ACCESS FULL     | T_XIFENFEI |   192 |   768 |     3   (0)| 00:00:01 |
---------------------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
   1 - filter("from$_subquery$_003"."rowlimit_$$_rownumber"<=CASE  WHEN (5>=0)
              THEN 5 ELSE 0 END +5 AND "from$_subquery$_003"."rowlimit_$$_rownumber">5)
   2 - filter(ROW_NUMBER() OVER ( ORDER BY INTERNAL_FUNCTION("ID") DESC
              )<=CASE  WHEN (5>=0) THEN 5 ELSE 0 END +5)
Statistics
----------------------------------------------------------
          0  recursive calls
          0  db block gets
          7  consistent gets
          0  physical reads
          0  redo size
        619  bytes sent via SQL*Net to client
        544  bytes received via SQL*Net from client
          2  SQL*Net roundtrips to/from client
          1  sorts (memory)
          0  sorts (disk)
          5  rows processed

传统分页写法

SQL> select id from (select id,rownum rn from (
  2  select id  from t_xifenfei order by id desc
  3  )) where rn<11 and rn>=6;
        ID
----------
       188
       187
       186
       185
       184
Execution Plan
----------------------------------------------------------
Plan hash value: 327151993
------------------------------------------------------------------------------------
| Id  | Operation             | Name       | Rows  | Bytes | Cost (%CPU)| Time     |
------------------------------------------------------------------------------------
|   0 | SELECT STATEMENT      |            |   192 |  4992 |     3   (0)| 00:00:01 |
|*  1 |  VIEW                 |            |   192 |  4992 |     3   (0)| 00:00:01 |
|   2 |   COUNT               |            |       |       |            |          |
|   3 |    VIEW               |            |   192 |  2496 |     3   (0)| 00:00:01 |
|   4 |     SORT ORDER BY     |            |   192 |   768 |     3   (0)| 00:00:01 |
|   5 |      TABLE ACCESS FULL| T_XIFENFEI |   192 |   768 |     3   (0)| 00:00:01 |
------------------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
   1 - filter("RN">=6 AND "RN"<11)
Statistics
----------------------------------------------------------
          0  recursive calls
          0  db block gets
          7  consistent gets
          0  physical reads
          0  redo size
        619  bytes sent via SQL*Net to client
        544  bytes received via SQL*Net from client
          2  SQL*Net roundtrips to/from client
          1  sorts (memory)
          0  sorts (disk)
          5  rows processed

从这里可以看出来两种sql分页写法，在小数据量上效率都差不多，但是明显TOP N的写法更加简单，更加灵活.如果数据量大可能还是需要自己写分页SQL。TOP N是通过ROW_NUMBER() OVER INTERNAL_FUNCTION(“ID”)和CASE WHEN内部转换实现分页功能.

官方文档创建表语句部分说明
在12c中,表支持默认列为sequence值，而且不用使用传统的触发器来实现该功能.



12c创建表使用默认sequence测试过程

SQL> select * from v$version;
BANNER                                                                               CON_ID
-------------------------------------------------------------------------------- ----------
Oracle Database 12c Enterprise Edition Release 12.1.0.0.2 - 64bit                         0
PL/SQL Release 12.1.0.0.2                                                                 0
CORE    12.1.0.0.2                                                                        0
TNS for Linux: Version 12.1.0.0.2                                                         0
NLSRTL Version 12.1.0.0.2                                                                 0
SQL> create table t_xifenfei
  2  (
  3  id number GENERATED ALWAYS as identity (
  4  start with 1
  5  increment by 1
  6  ),
  7  name varchar2(200)
  8  );
Table created.
SQL> insert into t_xifenfei(name) values('www.xifenfei.com');
1 row created.
SQL> commit;
Commit complete.
SQL> col name for a30
SQL> select * from t_xifenfei;
        ID NAME
---------- ------------------------------
         1 www.xifenfei.com
SQL> insert into t_xifenfei(name) values('www.orasos.com');
1 row created.
SQL> commit;
Commit complete.
SQL> select * from t_xifenfei;
        ID NAME
---------- ------------------------------
         1 www.xifenfei.com
         2 www.orasos.com
SQL> insert into t_xifenfei values(5,'www.xifenfei.com');
insert into t_xifenfei values(5,'www.xifenfei.com')
            *
ERROR at line 1:
ORA-32795: cannot insert into a generated always identity column
SQL> insert into t_xifenfei(name) values('www.xifenfei.com');
1 row created.
SQL> commit;
Commit complete.
SQL> select * from t_xifenfei;
        ID NAME
---------- ------------------------------
         1 www.xifenfei.com
         2 www.orasos.com
         3 www.xifenfei.com

补充说明
1.如果设置了列默认值为seq,则不能手工插入一个该列值否则报ORA-32795
2.通过10046跟踪该insert语句未发现trigger对应sql语句操作,比传统自己编写触发器效率原则上更加高