What is the effect of specifying the “ENABLE PLUGGABLE DATABASE” clause in a “CREATE
DATABASE” statement?
A.
It will create a multitenant container database (CDB) with only the root opened.
B.
It will create a CDB with root opened and seed read only.
C.
It will create a CDB with root and seed opened and one PDB mounted.
D.
It will create a CDB that must be plugged into an existing CDB.
E.
It will create a CDB with root opened and seed mounted.
Explanation:
* The CREATE DATABASE … ENABLE PLUGGABLE DATABASE SQL statement
creates a new CDB. If you do not specify the ENABLE PLUGGABLE DATABASE clause, then the
newly created database is a non-CDB and can never contain PDBs.
Along with theroot (CDB$ROOT), Oracle Database automatically creates aseed PDB
(PDB$SEED). The following graphic shows a newly created CDB:* Creating a PDB
Rather than constructing the data dictionary tables that define an empty PDB from scratch,
and then populating its Obj$ and Dependency$ tables, the empty PDB is created when the CDB
is created. (Here, we use empty to mean containing no customer-created artifacts.) It is referred
to as the seed PDB and has the name PDB$Seed. Every CDB non-negotiably contains a
seed PDB; it is non-negotiably always open in read-only mode. This has no conceptual
significance; rather, it is just an optimization device. The create PDB operation is implemented
as a special case of the clone PDB operation.
Why not “C”, if the states of the PDB can be: CLOSE, OPEN READ-ONLY, OPEN READ-WRITE, MIGRATE and MOUNT??
The root and seed are open, each in a different state?
Example 42-2 Changing the Open Mode of a PDB
This ALTER PLUGGABLE DATABASE statement changes the open mode of the current PDB to mounted.
ALTER PLUGGABLE DATABASE CLOSE IMMEDIATE;
The following statement changes the open mode of the current PDB to open read-only.
ALTER PLUGGABLE DATABASE OPEN READ ONLY;
A PDB must be in mounted mode to change its open mode to read-only or read/write unless you specify the FORCE keyword. The following statement changes the open mode of the current PDB from mounted or open read-only to open read-write.
ALTER PLUGGABLE DATABASE OPEN FORCE;
The following statement changes the open mode of the current PDB from mounted to migrate.
ALTER PLUGGABLE DATABASE OPEN UPGRADE;
http://docs.oracle.com/database/121/ADMIN/cdb_pdb_admin.htm#ADMIN14096
C – say seed opened. Seed is always read
B is correct. “ENABLE PLUGGABLE DATABASE” does not create PDB!!
B
B
wondercul points altogether, you just won a new reader.
What might you recommend about your submit that you
just made a few days ago? Any positive?
B
The answer is both A and B
B
It is obvious. ENABLE PLUGGABLE DATABSE creates a CDB. After the CDB is created, it is opened. The seed PDB$SEED is opened as READ ONLY, always.
B
B
B 是正确的;