Multitenant Feature of Oracle Database 12c - Helping customers reduce IT costs by streamlining consolidation, provisioning, upgrades, and more

1. Oracle 12c
Multitenant Feature

2. Overview
• A new option for Oracle Database 12c, Oracle Multitenant helps customers reduce
IT costs by streamlining consolidation, provisioning, upgrades, and more. It is
supported by a new architecture that allows a multitenant container database to
hold many pluggable databases. And it fully balances other options, including Oracle
Real Application Clusters and Oracle Active Data Guard. An existing database can be
simply adopted, with no change, as a pluggable database; and no changes are
needed in the other tiers of the application.

3. Container & Pluggable Database
• A CDB is very similar to a conventional
Oracle database. It’s main purpose is to
house the data dictionary for those
objects that are owned by the root
container and those that are accessible to
all PDBs. A single CDB can host multiple
PDBs.
• A PDB contains only information
pertaining to itself and hence only has
datafiles and tempfiles. It also has it’s
own data dictionary.

4. Creating a Container Database (CDB) - OUI
• We can use the Oracle Universal
Installer (OUI) to create a CDB
during the 12c software installation
by checking the “Create as
Container database” option on the
“Typical Installation Screen”. We
also have an option to create a
single PDB at this time.

5. Creating a Container Database (CDB) - OUI
• We can create a CDB on the
“Database Identifiers” screen as
well.

6. Creating a Container Database (CDB) - DBCA
• A CDB can be created using the
Database Configuration Assistant
(DBCA) also. The "Creation Mode"
page allows us to enter the default
installation configuration details
directly.

7. Creating a Container Database (CDB) - DBCA
• If we choose the "Advanced
Mode" option, we can create a
CDB and multiple PBDs in one go.

8. Creating a Container Database (CDB) – Manual Creation
• We can also create a CDB manually. The following script can be used for the same –
• When the ENABLE PLUGGABLE DATABASE clause is present, the database is created as a CDB with both
root and seed. The SEED FILE_NAME_CONVERT clause is used to determine the seed file names based on
the root file names. We can also specify the seed datafiles explicitly.
• SEED
• SYSTEM DATAFILE '/u01/app/oracle/oradata/cdb1/pdbseed/system01.dbf' SIZE 700M REUSE
• AUTOEXTEND ON NEXT 10240K MAXSIZE UNLIMITED
• EXTENT MANAGEMENT LOCAL
• SYSAUX DATAFILE '/u01/app/oracle/oradata/cdb1/pdbseed/sysaux01.dbf' SIZE 550M REUSE
• AUTOEXTEND ON NEXT 10240K MAXSIZE UNLIMITED

9. Managing a Pluggable Database (PDB) - DBCA
• On the opening “Database
Operation” screen of DBCA, a
new option has been added
which allows us to manage
pluggable databases of an
existing container database.

10. Managing a Pluggable Database (PDB) - DBCA
• Resulting screen options.

11. Creating a Pluggable Database (PDB) - DBCA
• On choosing the first option
“Create a Pluggable Database”
on the last screen, we are asked
to select the Container
Database where the PDB would
be created.

12. Creating a Pluggable Database (PDB) - DBCA
• The first option “Create a new
Pluggable Database” can be used
to create a fresh PDB. If we want
to plug a previously unplugged
database, then one of the rest
two options, PDB Archive or PDB
File Set, can be used. These
options can be used to match the
format of the files containing the
unplugged PDB.

13. Creating a Pluggable Database (PDB) - DBCA
• On this screen, we enter the PDB
name, database location and
admin credentials.

14. Creating a Pluggable Database (PDB) - DBCA
• The new PDB is created as a
clone of the seed database we
created during the Container
Database creation.

15. Unplugging a Pluggable Database (PDB) - DBCA
• On the "Manage Pluggable
Databases" screen shown
previously, we can select the
"Unplug a Pluggable Database"
option to unplug a PDB. On the
resulting screen, we select the
container database that
houses the pluggable database
to be unplugged.

16. Unplugging a Pluggable Database (PDB) - DBCA
• After we select the PDB to
unplug, we need to decide
whether to use a pluggable
database archive or file set and
then enter the appropriate
location details.

17. Creating a Pluggable Database (PDB)
using Archive or File Set - DBCA
• We can select either of the
two options, “Create Pluggable
Database From PDB Archive"
or "Create Pluggable Database
using PDB File Set“ and enter
the location details of the
required files.

18. Creating a Pluggable Database (PDB)
using Archive or File Set - DBCA
• Here we enter the
pluggable database
name, database
location and admin
credentials.

19. Deleting a Pluggable Database (PDB) - DBCA
• After choosing the container
database on the “Database
List” screen, we can select the
pluggable database that we
wish to delete from the drop
down list on the resulting
screen.

20. Configuring a Pluggable Database (PDB) - DBCA
• After choosing the container
database on the “Database
List” screen, we can select the
pluggable database that we
wish to configure from the
drop down list on the
“Pluggable Database List”
screen. On the resulting
“Pluggable Database Options”
screen, we can choose to
configure Label Security.

21. Creating a Pluggable Database (PDB) - Manually
• To create a new PDB from a seed database, we need to tell Oracle where the file should be placed.
• CONN / AS SYSDBA
• CREATE PLUGGABLE DATABASE pdb2 ADMIN USER pdb_adm IDENTIFIED BY Password1
FILE_NAME_CONVERT=('/u01/app/oracle/oradata/cdb1/pdbseed/','/u01/app/oracle/oradata/cdb1/pdb2/');
• Alternatively,
• CONN / AS SYSDBA
• ALTER SESSION SET
PDB_FILE_NAME_CONVERT='/u01/app/oracle/oradata/cdb1/pdbseed/','/u01/app/oracle/oradata/cdb1/pdb3/';
• CREATE PLUGGABLE DATABASE pdb3 ADMIN USER pdb_adm IDENTIFIED BY Password1;
• We can see the PDBs that are present by querying the DBA_PDBS and V$PDBS views.
• SELECT pdb_name, status FROM dba_pdbs ORDER BY pdb_name;
• SELECT name, open_mode FROM v$pdbs ORDER BY name;
• The PDBs are created with the status of ‘NEW’. They must be opened in READ WRITE mode for the integration
with the CDB to be complete.
• ALTER PLUGGABLE DATABASE pdb2 OPEN READ WRITE;

22. Unplugging a Pluggable Database (PDB) - Manually
• Before unplugging a PDB, we must make sure it is closed.
• ALTER PLUGGABLE DATABASE pdb2 CLOSE;
• ALTER PLUGGABLE DATABASE pdb2 UNPLUG INTO '/u01/app/oracle/oradata/cdb1/pdb2/pdb2.xml';
• We can delete the PDB, choosing to keep the files on the file system.
• DROP PLUGGABLE DATABASE pdb2 KEEP DATAFILES;

23. Plugging a Pluggable Database (PDB) - Manually
We need to first check if the PDB is compatible with the CDB.
SET SERVEROUTPUT ON
DECLARE
l_result BOOLEAN;
BEGIN
l_result := DBMS_PDB.check_plug_compatibility( pdb_descr_file => '/u01/app/oracle/oradata/cdb1/pdb2/pdb2.xml',
pdb_name => 'pdb2');
IF l_result THEN
DBMS_OUTPUT.PUT_LINE('compatible');
ELSE
DBMS_OUTPUT.PUT_LINE('incompatible');
END IF;
END;
/
compatible
PL/SQL procedure successfully completed.
CREATE PLUGGABLE DATABASE pdb5 USING '/u01/app/oracle/oradata/cdb1/pdb2/pdb2.xml'
FILE_NAME_CONVERT=('/u01/app/oracle/oradata/cdb1/pdb2/','/u01/app/oracle/oradata/cdb1/pdb5/');
Or,
CREATE PLUGGABLE DATABASE pdb2 USING '/u01/app/oracle/oradata/cdb1/pdb2/pdb2.xml' NOCOPY TEMPFILE REUSE;
ALTER PLUGGABLE DATABASE pdb2 OPEN READ WRITE;

24. Cloning a Pluggable Database (PDB) - Manually
Cloning an existing local PDB is similar to creating a new PDB from the seed PDB, except that now we would be using a non-seed PDB as
a source.
ALTER PLUGGABLE DATABASE pdb3 CLOSE;
ALTER PLUGGABLE DATABASE pdb3 OPEN READ ONLY;
CREATE PLUGGABLE DATABASE pdb4 FROM pdb3
FILE_NAME_CONVERT=('/u01/app/oracle/oradata/cdb1/pdb3/','/u01/app/oracle/oradata/cdb1/pdb4/');
ALTER PLUGGABLE DATABASE pdb4 OPEN READ WRITE;
-- Switch the source PDB back to read/write
ALTER PLUGGABLE DATABASE pdb3 CLOSE;
ALTER PLUGGABLE DATABASE pdb3 OPEN READ WRITE;
We can also clone from a remote PDB using a database link in the local CBD.
CREATE PLUGGABLE DATABASE pdb5 FROM remote_pdb5@remotecdb1
FILE_NAME_CONVERT=('/u01/app/oracle/oradata/cdb1/remote_pdb5/','/u01/app/oracle/oradata/cdb1/pdb5/');
ALTER PLUGGABLE DATABASE pdb4 OPEN READ WRITE;
*This functionality does not work properly in the 12.1.0.1 release of the database.

25. Deleting a Pluggable Database (PDB) - Manually
When dropping a PDB, we can choose to keep or drop the associated datafiles. The PDBs must be closed before dropping.
ALTER PLUGGABLE DATABASE pdb2 CLOSE;
DROP PLUGGABLE DATABASE pdb2 KEEP DATAFILES;
ALTER PLUGGABLE DATABASE pdb3 CLOSE;
DROP PLUGGABLE DATABASE pdb3 INCLUDING DATAFILES;
SELECT name, open_mode FROM v$pdbs ORDER BY name;
NAME OPEN_MODE
------------------------------ ----------
PDB$SEED READ ONLY
PDB1 MOUNTED

26. Oracle Documentation & References
• Oracle Database 12c: Introduction to a Multitenant Environment with Tom Kyte -
http://www.youtube.com/watch?v=2MrouEW9j88&feature=youtu.be
• White Paper - http://www.oracle.com/technetwork/database/multitenant/overview/multitenant-
wp-12c-2078248.pdf
• Data Sheet - http://www.oracle.com/technetwork/database/multitenant-ds-12c-1951720.pdf