1z0-182 Exam Dumps - Oracle Database Questions and Answers

A.True. Multiple sessions with different users are possible.

B.False. Buffer cache and redo log buffer are in SGA, not large pool.

C.True. Session tracks login state.

D.True. Each process has its own PGA.

E.False. Connection is the network link; session is the state.

F.True. Same user can have multiple sessions (e.g., via different terminals).

A.False. Data files open in OPEN.

B.False. Redo logs open in OPEN.

C.False. PFILE/SPFILE is read at NOMOUNT.

D.False. SGA is allocated at NOMOUNT.

E.True. Alert log records mount event.

F.True. Control files are read in MOUNT.

A.False. No checkpoint occurs with ABORT.

B.False. Instance recovery, not media recovery, is needed.

C.True. Crash recovery rolls back uncommitted changes on startup.

D.False. Files aren’t closed cleanly with ABORT.

E.True. Shutdown doesn’t roll back; recovery does.

A.False. IOTs require immediate segment creation.

B.False. SYS-owned tables don’t use deferred creation.

C.True. Default since 11gR2, continued in 23ai.

D.True. Indexes inherit this attribute unless overridden.

E.True. Sessions can alter this via DEFERRED_SEGMENT_CREATION.

A.True. Metrics (e.g., V$SYSMETRIC) use thresholds for alerts.

B.False. Metrics aren’t tied to email notifications directly.

C.True. Metrics measure rates (e.g., IOPS, transactions/sec).

D.False. EMCC uses metrics, but they’re DB-level, not EM-specific.

E.False. Metrics exist in the DB, not just EMCC.

A.True. sqlplus @script.sql works from shell scripts.

B.False. RMAN uses its own client, not SQL*Plus.

C.False. Bundled with Oracle DB software.

D.False. Command-line only; no GUI in 23ai.

E.True. @script runs scripts interactively.

F.True. Commands like SHOW PARAMETER are unique.

A.True. Integrates with MOS for patches and support.

B.True. Manages Exadata, etc.

C.True. Covers WebLogic and other middleware.

D.False. Web-based, but not built into the DB.

E.False. Can manage stopped instances via agents.

Database links enable cross-database queries in Oracle. Let’s analyze each option with extensive detail:

A. A public database link can be created only by SYS.

Explanation:False. Any user with the CREATE PUBLIC DATABASE LINK privilege (not just SYS) can create a public link (e.g., CREATE PUBLIC DATABASE LINK remote_db CONNECT TO scott IDENTIFIED BY tiger USING 'orcl'). While SYS typically has this privilege, it’s not exclusive to SYS.

Mechanics:Privilege is granted via GRANT CREATE PUBLIC DATABASE LINK TO user;. Public links are accessible to all users in the local DB.

Why Incorrect:Overly restrictive; Oracle’s security model allows delegation.

B. A database link can be created only between two Oracle databases.

Explanation:False. Database links can connect to non-Oracle databases using Oracle Heterogeneous Services or gateways (e.g., ODBC or JDBC drivers), such as linking to SQL Server. Example: CREATE DATABASE LINK mssql_link USING 'hsodbc';.

Mechanics:Requires configuration of hs_ parameters in init.ora and a gateway listener.

Historical Note:Heterogeneous links were introduced in 8i, expanded in 23ai for cloud integration.

C. A database link created in a database allows a connection from that database's instance to the target database's instance, but not vice versa.

Explanation:True. A database link is unidirectional; it enables queries from the local instance to the remote instance (e.g., SELECT * FROM emp@remote_db), but the remote instance can’t use it to query back unless a separate link is created there.

Mechanics:Stored in DBA_DB_LINKS, the link defines a one-way connection via a TNS alias or connect string.

Practical Use:Ensures controlled access; bidirectional access requires explicit configuration.

Edge Case:Loops are prevented unless explicitly designed with mutual links.

D. A public database link can be used by a user connected to the local database instance to connect to any schema in the remote database instance.

Explanation:False. Public links allow all local users to use them, but access to remote schemas depends on the link’s credentials (e.g., CONNECT TO scott) and the user’s remote privileges. “Any schema” overstates it; access is limited to what the link’s user can see.

Why Incorrect:Misrepresents privilege scope; remote schema access isn’t universal.

E. Private database link creation requires the same user to exist in both the local and the remote databases.

Explanation:False. A private link (e.g., CREATE DATABASE LINK my_linkCONNECT TO scott IDENTIFIED BY tiger USING 'orcl') requires the remote user (scott) to exist, but the local creator (e.g., HR) need not match. The link is owned locally and authenticated remotely.

Mechanics:Only the CREATE DATABASE LINK privilege is needed locally.

Dynamic service registration allows a database to automatically register its services with a listener without manual configuration in LISTENER.ORA. Let’s analyze each option:

A. The definition for LISTENER_1 requires a CONNECT_DATA section to enable dynamic service registration.

Explanation:False. The CONNECT_DATA section is part of a client-side TNSNAMES.ORA entry for connecting to a service, not for listener registration. Dynamic registration is handled by the database’s LREG (Listener Registration) process, which uses the LOCAL_LISTENER parameter to locate the listener’s address (e.g., host1.abc.com:1521). No CONNECT_DATA is needed in the listener address definition itself. This option confuses client connection syntax with listener configuration.

Mechanics:The listener address in TNSNAMES.ORA (LISTENER_1) is sufficient for LREG to find and register with it, as long as the listener is running at that address.

B. LISTENER_1 must also be defined in the LISTENER.ORA file to enable dynamic service registration.

Explanation:False. Dynamic registration doesn’t require the listener to be explicitly defined in LISTENER.ORA. The LOCAL_LISTENER parameter pointing to LISTENER_1 (resolved via TNSNAMES.ORA) tells LREG where to register services. If the listener is running on host1.abc.com:1521, LREG will find it without a LISTENER.ORA entry. However, LISTENER.ORA is needed tostartthe listener process, but that’s separate from dynamic registration.

Practical Note:If LISTENER.ORA isn’t configured, a default listener might run on port 1521, but the question implies LISTENER_1 is operational.

C. The LREG process registers services dynamically with the LISTENER_1 listener.

Explanation:True. In Oracle 23ai, the LREG background process (replacing PMON’s registration role in earlier versions) dynamically registers database services with listeners specified by LOCAL_LISTENER. Here, LOCAL_LISTENER=LISTENER_1 resolves to host1.abc.com:1521 via TNSNAMES.ORA. LREG periodically sends service information (e.g., service names, instance details) to the listener, enabling clients to connect without static configuration.

Mechanics:LREG uses the TNS alias (LISTENER_1) to locate the listener’s IP and port, registers services like orcl or orclpdb, and updates the listener’s service table. This happens automatically every 60 seconds or on significant events (e.g., instance startup).

D. Dynamic service registration cannot be used for this database instance.

Explanation:False. The setup (LOCAL_LISTENER set and a valid TNSNAMES.ORA entry) explicitly supports dynamic registration. No blockers (e.g., REGISTRATION_EXCLUDED_LISTENERS) are mentioned, so LREG can function normally.

E. There are two listeners named LISTENER and LISTENER_1 running simultaneously using port 1521 on the same host as the database in LISTENERS.

Explanation:False. The question mentions only LISTENER_1 in the SPFILE and TNSNAMES.ORA. There’s no evidence of a second listener (LISTENER) or a LISTENERS configuration (possibly a typo). Two listeners can’t share the same port (1521) on the same host due to port conflicts unless explicitly configured with different IPs, which isn’t indicated here.

A.True. Any PDB except PDB$SEED can be dropped.

B.False. Source PDBs of refreshable clones can be dropped after cloning.

C.False. Dropping an application root requires explicit handling of PDBs.

D.False. Relocation doesn’t mandate dropping the source PDB.