OCP Core Administration And Cdb Pdb Architecture — 40 Questions

Question 1

What is the default state of a PDB after creating it using the CREATE PLUGGABLE DATABASE command?

Accepted Answer

MOUNTED. When you create a pluggable database (PDB) with the CREATE PLUGGABLE DATABASE statement in Oracle Multitenant, the PDB is created in MOUNTED state by default. This means the PDB's data files are associated with the instance, but the PDB is not open for user access. You must explicitly open the PDB with ALTER PLUGGABLE DATABASE ... OPEN to make it available. The MOUNTED state is a transitional state that allows you to perform operations like opening in restricted mode or upgrading before making it available to users.

Answer

READ WRITE

Answer

OPEN UPGRADE

Answer

READ ONLY

Question 2

A PDB is in 'READ WRITE' mode. You need to perform a maintenance task that requires the PDB to be in 'RESTRICTED' mode. Which command achieves this?

Accepted Answer

ALTER PLUGGABLE DATABASE PDB1 CLOSE IMMEDIATE; ALTER PLUGGABLE DATABASE PDB1 OPEN RESTRICTED;. To move a PDB into restricted mode, you must use ALTER PLUGGABLE DATABASE ... CLOSE followed by OPEN RESTRICTED.

Answer

ALTER SYSTEM SET RESTRICTED_SESSION=TRUE;

Answer

ALTER PLUGGABLE DATABASE PDB1 UPGRADE;

Answer

ALTER DATABASE PDB1 RESTRICTED;

Answer

ALTER PLUGGABLE DATABASE PDB1 OPEN RESTRICTED

Question 3

When managing local and common users in a 23ai CDB, which TWO of the following statements are correct?

Accepted Answer

Common users can only be created in the root container.. Option A is correct because common users are defined once in the root container (CDB$ROOT) and are then visible across all containers, so they must be created while connected to the root. Option D is correct because Oracle enforces that common user names in a CDB begin with the C## (or c##) prefix, which distinguishes them from local users. Option B is wrong because local users exist only in the specific PDB where they are created, not automatically in all PDBs. Option C is wrong because local roles belong to a single PDB and cannot be granted to common users, who operate across containers. Option E is wrong because local users cannot grant privileges to common users; privilege grants involving common users must be performed by appropriately privileged common users in the root.

Answer

Local users are automatically created in all PDBs by default.

Answer

Common users can grant local roles to other common users.

Answer

Local users can grant privileges to common users.

Question 4

You are configuring a new CDB and want to ensure that PDBs use a common set of initialization parameters while allowing for specific overrides. Which parameter must be configured at the CDB level to allow local PDB parameter overrides?

Accepted Answer

PDB_SPFILE. The PDB_SPFILE parameter in the CDB root allows managing individual PDB spfiles.

Answer

CONTAINER_DATA

Answer

PDB_FILE_NAME_CONVERT

Answer

CDB_PARAMETER_OVERRIDE

Question 5

You are creating a new PDB from an existing one using the CREATE PLUGGABLE DATABASE command. Which clause must you include to ensure the new PDB has a different name and storage location?

Accepted Answer

FILE_NAME_CONVERT. The CREATE PLUGGABLE DATABASE statement requires the file_name_convert clause to define the directory structure for the new PDB datafiles.

Answer

MOVE DATAFILES

Answer

USING STORAGE MAP

Answer

SNAPSHOT COPY

Question 6

When performing a 'Refreshable PDB Switchover', what is the state of the source PDB?

Accepted Answer

READ ONLY. During a switchover, the source PDB is converted to a refreshable PDB.

Answer

RESTRICTED

Answer

READ WRITE

Answer

MOUNTED

Question 7

Which view should you query to see the current status of all PDBs in the CDB?

Accepted Answer

DBA_PDBS. DBA_PDBS provides the status of all PDBs in the CDB.

Answer

ALL_PDBS

Answer

V$PDBS

Answer

CDB_PDBS

Question 8

You want to limit the amount of memory a specific PDB can consume in a CDB. Which parameter should you configure?

Accepted Answer

PDB_SGA_TARGET. The SGA_TARGET at the PDB level is managed via the PDB_SGA_TARGET parameter.

Answer

CONTAINER_MEMORY_LIMIT

Answer

MEMORY_TARGET

Answer

SGA_MAX_SIZE_PDB

Question 9

Which directory contains the Alert log for the CDB?

Accepted Answer

ORACLE_BASE/diag/rdbms/.... The Automatic Diagnostic Repository (ADR) stores all CDB diagnostic information.

Answer

/var/log/oracle

Answer

ORACLE_BASE/admin

Answer

ORACLE_HOME/dbs

Question 10

You are configuring a PDB to use Local Undo. What requirement must be met before setting the UNDO_TABLESPACE parameter?

Accepted Answer

The PDB must be closed. To set the UNDO_TABLESPACE parameter for a PDB to use Local Undo, the PDB must be closed. This is because the undo tablespace is a critical part of the PDB's physical structure, and changing it requires the PDB to be in a quiesced state. The parameter can be set while the PDB is closed, and then the PDB can be reopened.

Answer

The CDB must be in read-only mode

Answer

The CDB must be in ARCHIVELOG mode

Answer

The PDB must be a proxy PDB

Question 11

In a 23ai CDB, which view reveals the mapping between PDBs and their associated services?

Accepted Answer

V$SERVICES. V$SERVICES shows the service name and the associated PDB ID.

Answer

DBA_SERVICES

Answer

CDB_SERVICES

Answer

V$PDBS

Question 12

Which initialization parameter determines the maximum number of PDBs allowed in a CDB?

Accepted Answer

MAX_PDB_CONTAINERS. MAX_PDB_CONTAINERS defines the hard limit for PDBs in a CDB.

Answer

DB_FILES

Answer

PDB_LIMIT

Answer

CONTAINERS_MAX

Question 13

Which privilege is required to perform a PDB unplug operation?

Accepted Answer

SYSDBA. SYSDBA or SYSOPER at the CDB root is required.

Answer

RESOURCE

Answer

CONNECT

Answer

PDB_DBA

Question 14

How can you verify if a PDB is encrypted?

Accepted Answer

Query V$ENCRYPTION_WALLET. Querying DBA_PDB_KE_STATE or checking V$ENCRYPTION_WALLET is the standard method.

Answer

Check PDB_ENCRYPTED column in V$PDBS

Answer

Use SQL*Plus SHOW PARAMETER

Answer

Check the alert log

Question 15

If you want to use a PDB as a template for other PDBs, what state must the template PDB be in?

Accepted Answer

READ ONLY. The PDB must be open in READ ONLY mode to be used as a template.

Answer

MOUNTED

Answer

RESTRICTED

Answer

READ WRITE

Question 16

You need to capture PDB performance data. Which feature allows you to capture an AWR snapshot for a specific PDB?

Accepted Answer

DBMS_WORKLOAD_REPOSITORY.CREATE_SNAPSHOT. DBMS_WORKLOAD_REPOSITORY.CREATE_SNAPSHOT is used for AWR snapshots at the container level.

Answer

ALTER PDB SNAPSHOT

Answer

AWR_PDB_SNAPSHOT

Answer

DBMS_PERF.CAPTURE

Question 17

What is the purpose of the 'CDB_ROOT'?

Accepted Answer

To store system metadata. The CDB root manages system-wide objects and metadata.

Answer

To store PDB$SEED

Answer

To store user data

Answer

To manage PDB recovery

Question 18

Which view displays the PDBs that are currently open in the CDB?

Accepted Answer

V$PDBS. V$PDBS shows the status of all PDBs in the instance.

Answer

V$CONTAINERS

Answer

DBA_PDB_STATUS

Answer

CDB_PDB_STATUS

Question 19

What happens to existing sessions when you issue 'ALTER PLUGGABLE DATABASE PDB1 CLOSE'?

Accepted Answer

Sessions are killed if IMMEDIATE is specified. By default, the command fails if sessions exist unless 'IMMEDIATE' is used.

Answer

Sessions are migrated

Answer

The database waits indefinitely

Answer

Sessions remain active

Question 20

Which dictionary view tracks the PDB creation time?

Accepted Answer

CDB_PDBS. CDB_PDBS contains the creation time of all PDBs in the CDB.

Answer

DBA_PDB_HISTORY

Answer

DBA_OBJECTS

Answer

V$PDBS