Wednesday, September 2, 2015

Multitenant : Connecting to Container Databases (CDB) and Pluggable Databases (PDB) in Oracle Database 12c Release 1 (12.1)

Connecting to a Container Database (CDB)

Connecting to the root of a container database is the same as that of any previous database instance. On the database server you can use OS Authentication.

$ export ORACLE_SID=cdb1
$ sqlplus / as sysdba

SQL*Plus: Release 12.1.0.1.0 Production on Mon Aug 26 15:29:49 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, OLAP, Advanced Analytics and Real Application Testing options

SQL>
You can connect to other common users in similar way.

SQL> CONN system/password
Connected.
SQL>
The V$SERVICES views can be used to display available services from the database.

COLUMN name FORMAT A30

SELECT name, pdb
FROM    v$services
ORDER BY name;

NAME                                        PDB
------------------------------ ------------------------------
SYS$BACKGROUND                 CDB$ROOT
SYS$USERS                                 CDB$ROOT
cdb1                                               CDB$ROOT
cdb1XDB                                          CDB$ROOT
pdb1                                                    PDB1
pdb2                                                     PDB2

6 rows selected.

SQL>
The lsnrctl utility allows you to display the available services from the command line.

$ lsnrctl service

LSNRCTL for Linux: Version 12.1.0.1.0 - Production on 20-MAY-2014 09:01:34

Copyright (c) 1991, 2013, Oracle.  All rights reserved.

Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=EXTPROC1521)))
Services Summary...
Service "cdb1" has 1 instance(s).
  Instance "cdb1", status READY, has 1 handler(s) for this service...
    Handler(s):
      "DEDICATED" established:0 refused:0 state:ready
         LOCAL SERVER
Service "cdb1XDB" has 1 instance(s).
  Instance "cdb1", status READY, has 1 handler(s) for this service...
    Handler(s):
      "D000" established:0 refused:0 current:0 max:1022 state:ready
         DISPATCHER
         (ADDRESS=(PROTOCOL=tcp)(HOST=ol6-121.localdomain)(PORT=21196))
Service "pdb1" has 1 instance(s).
  Instance "cdb1", status READY, has 1 handler(s) for this service...
    Handler(s):
      "DEDICATED" established:0 refused:0 state:ready
         LOCAL SERVER
Service "pdb2" has 1 instance(s).
  Instance "cdb1", status READY, has 1 handler(s) for this service...
    Handler(s):
      "DEDICATED" established:0 refused:0 state:ready
         LOCAL SERVER
The command completed successfully
$
Connections using services are unchanged from previous versions.

SQL> -- EZCONNECT
SQL> CONN system/password@//localhost:1521/cdb1
Connected.
SQL>

SQL> -- tnsnames.ora
SQL> CONN system/password@cdb1
Connected.
SQL>
The connection using a TNS alias requires an entry in the "$ORACLE_HOME/network/admin/tnsnames.ora" file, such as the one shown below.

CDB1 =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = ol6-121.localdomain)(PORT = 1521))
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = cdb1)
    )
  )
Displaying the Current Container

The SHOW CON_NAME and SHOW CON_ID commands in SQL*Plus display the current container name and ID respectively.

SQL> SHOW CON_NAME

CON_NAME
------------------------------
CDB$ROOT
SQL>

SQL> SHOW CON_ID

CON_ID
------------------------------
1
SQL>
They can also be retrieved using the SYS_CONTEXT function.

SELECT SYS_CONTEXT('USERENV', 'CON_NAME')
FROM   dual;

SYS_CONTEXT('USERENV','CON_NAME')
--------------------------------------------------------------------------------
CDB$ROOT

SQL>


SELECT SYS_CONTEXT('USERENV', 'CON_ID')
FROM   dual;

SYS_CONTEXT('USERENV','CON_ID')
--------------------------------------------------------------------------------
1

SQL>

Switching Between Containers


When logged in to the CDB as an appropriately privileged user, the ALTER SESSION command can be used to switch between containers within the container database.

SQL> ALTER SESSION SET container = pdb1;

Session altered.

SQL> SHOW CON_NAME

CON_NAME
------------------------------
PDB1

SQL> ALTER SESSION SET container = cdb$root;

Session altered.

SQL> SHOW CON_NAME

CON_NAME
------------------------------
CDB$ROOT
SQL>

Connecting to a Pluggable Database (PDB)


Direct connections to pluggable databases must be made using a service. Each pluggable database automatically registers a service with the listener. This is how any application will connect to a pluggable database, as well as administrative connections.

SQL> -- EZCONNECT
SQL> CONN system/password@//localhost:1521/pdb1
Connected.
SQL>

SQL> -- tnsnames.ora
SQL> CONN system/password@pdb1
Connected.
SQL>
The connection using a TNS alias requires an entry in the "$ORACLE_HOME/network/admin/tnsnames.ora" file, such as the one shown below.

PDB1 =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = ol6-121.localdomain)(PORT = 1521))
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = pdb1)
    )
  )
PDB users with the SYSDBA, SYSOPER, SYSBACKUP, or SYSDG privilege can connect to a closed PDB. All other PDB users can only connect when the PDB is open. As with regular databases, the PDB users require the CONNECT SESSION privilege to enable connections.

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