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- December 5, 2024
Question 41
Which SQL statement is used to lock a table in Oracle?
A) LOCK TABLE table_name;
B) ALTER TABLE LOCK table_name;
C) LOCK table_name;
D) LOCK TABLE table_name IN EXCLUSIVE MODE;
Correct Answer: D) LOCK TABLE table_name IN EXCLUSIVE MODE;
Explanation: The correct SQL statement to lock a table in Oracle is LOCK TABLE table_name IN EXCLUSIVE MODE.
Question 42
Which of the following options provides the ability to rollback a transaction in Oracle?
A) UNDO
B) ROLLBACK TO SAVEPOINT
C) RESTORE
D) REVERT
Correct Answer: B) ROLLBACK TO SAVEPOINT
Explanation: ROLLBACK TO SAVEPOINT allows rolling back part of a transaction to a specified savepoint.
Question 43
Which Oracle process is responsible for generating redo entries?
A) DBWn
B) SMON
C) LGWR
D) PMON
Correct Answer: C) LGWR
Explanation: The LGWR (Log Writer) process generates redo entries that are written to the redo log files to record database changes.
Question 44
Which of the following views in Oracle provides information about current system performance metrics?
A) V$SESSION
B) V$SYSSTAT
C) DBA_DATA_FILES
D) DBA_USERS
Correct Answer: B) V$SYSSTAT
Explanation: The V$SYSSTAT view provides information about current system performance metrics, such as CPU usage and I/O statistics.
Question 45
Which Oracle utility is used for block-level recovery of database files?
A) RMAN
B) Data Pump
C) LogMiner
D) Export/Import
Correct Answer: A) RMAN
Explanation: RMAN (Recovery Manager) is used for backup and recovery operations, including block-level recovery of database files.
Question 46
Which of the following Oracle background processes frees unused memory from the SGA?
A) DBWn
B) PMON
C) CKPT
D) SMON
Correct Answer: D) SMON
Explanation: The SMON (System Monitor) process is responsible for freeing up unused memory and performing instance recovery after a crash.
Question 47
Which of the following SQL statements enables flashback mode in Oracle?
A) ALTER SYSTEM ENABLE FLASHBACK;
B) ALTER DATABASE FLASHBACK ON;
C) ENABLE FLASHBACK MODE;
D) ALTER SYSTEM START FLASHBACK;
Correct Answer: B) ALTER DATABASE FLASHBACK ON;
Explanation: The correct SQL statement to enable flashback mode in Oracle is ALTER DATABASE FLASHBACK ON.
Question 48
Which of the following is used to enforce referential integrity between tables in Oracle?
A) Indexes
B) Foreign Keys
C) Sequences
D) Views
Correct Answer: B) Foreign Keys
Explanation: Foreign keys enforce referential integrity by ensuring that a column value in one table corresponds to a valid value in another table.
Question 49
Which of the following statements is true about Oracle’s Automatic Storage Management (ASM)?
A) It is used to manage table spaces.
B) It simplifies database storage management by automating the storage of database files.
C) It optimizes SQL query performance.
D) It provides automatic backups for the database.
Correct Answer: B) It simplifies database storage management by automating the storage of database files.
Explanation: ASM automates and simplifies the management of database storage by organizing files into disk groups.
Question 50
Which of the following SQL statements modifies a table to add a new column?
A) MODIFY TABLE ADD COLUMN column_name;
B) ALTER TABLE table_name ADD column_name;
C) INSERT COLUMN column_name INTO table_name;
D) UPDATE TABLE table_name ADD COLUMN column_name;
Correct Answer: B) ALTER TABLE table_name ADD column_name;
Explanation: The correct SQL statement to add a new column to a table is ALTER TABLE ADD COLUMN.
