Oracle Multitenant Architecture Flashcards

In Oracle Multitenant architecture, what does CDB stand for?

Answer: Container Database

CDB stands for Container Database, which is the top-level database that can host multiple Pluggable Databases (PDBs).

Which component of a CDB serves as a read-only, system-supplied template for creating new PDBs?

Answer: PDB$SEED

PDB$SEED is the read-only seed PDB provided by Oracle that acts as a template from which new Pluggable Databases are created.

What is the maximum number of PDBs supported in a single Oracle 12.2+ CDB?

Answer: 4096

Oracle 12.2 and later supports up to 4096 PDBs in a single CDB, a significant expansion from the 252-PDB limit in Oracle 12.1.

Which Oracle dynamic performance view provides real-time information about all containers (root, seed, and PDBs) in the current CDB?

Answer: V$CONTAINERS

V$CONTAINERS is the dynamic performance view that lists every container in the CDB including CDB$ROOT, PDB$SEED, and all user-created PDBs.

To switch a DBA session from CDB$ROOT to a PDB named SALESPDB without disconnecting, which SQL command is used?

Answer: ALTER SESSION SET CONTAINER = SALESPDB

ALTER SESSION SET CONTAINER = switches the current session context from the root to the specified PDB without requiring a reconnection.

What does setting LOCAL_UNDO = TRUE at the CDB level enable in Oracle Multitenant?

Answer: Each PDB maintains its own dedicated undo tablespace rather than sharing a CDB-level undo tablespace

LOCAL_UNDO = TRUE configures each PDB to own its individual undo tablespace, improving isolation and enabling PDB-level Flashback Database operations.

When creating a new PDB using CREATE PLUGGABLE DATABASE, which clause is typically used to map source datafile paths to the new PDB's target file locations?

Answer: FILE_NAME_CONVERT

FILE_NAME_CONVERT maps source datafile path patterns to target path patterns, telling Oracle where to place the new PDB's datafiles during creation or plug-in.