Oracle OCP 1Z0-050（81-90题）解析
QUESTION 81:
You enabled Flashback Data Archive on the INVENTORY table. Which DDL operation is supported on the table after enabling Flashback Data Archive?
A. Partition the table
B. Truncate the table.
C. Drop the table.
D. Rename a column in the table.
E. Add a column to the table.
Answer: E
解析：
参考Oracle官方文档：
https://docs.oracle.com/cd/E11882_01/appdev.112/e41502/adfns_flashback.htm#ADFNS01011
DDL Statements on Tables Enabled for Flashback Data Archive
Flashback Data Archive supports only these DDL statements:
ALTER TABLE statement that does any of the following:
Adds, drops, renames, or modifies a column
Adds, drops, or renames a constraint
Drops or truncates a partition or subpartition operation
TRUNCATE TABLE statement
RENAME statement that renames a table
Flashback Data Archive does not support DDL statements that move, split, merge, or coalesce partitions or subpartitions, move tables, or convert LONG columns to LOB columns.
For example, the following DDL statements cause error ORA-55610 when used on a table enabled for Flashback Data Archive:
ALTER TABLE statement that includes an UPGRADE TABLE clause, with or without an INCLUDING DATA clause
ALTER TABLE statement that moves or exchanges a partition or subpartition operation
DROP TABLE statement
If you must use unsupported DDL statements on a table enabled for Flashback Data Archive, use the DBMS_FLASHBACK_ARCHIVE.DISASSOCIATE_FBA procedure to disassociate the base table from its Flashback Data Archive. To reassociate the Flashback Data Archive with the base table afterward, use the DBMS_FLASHBACK_ARCHIVE.REASSOCIATE_FBA procedure.
Flashback Data Archive Scenarios
Scenario: Using Flashback Data Archive to Enforce Digital Shredding
Scenario: Using Flashback Data Archive to Access Historical Data
Scenario: Using Flashback Data Archive to Generate Reports
Scenario: Using Flashback Data Archive for Auditing
Scenario: Using Flashback Data Archive to Recover Data
QUESTION 82:
You are managing an Oracle Database 11g database with ASM storage. The ASM disk group has the COMPATIBLE.ASM attribute set to 11.1. Which statements are true regarding extent management and allocation units in the ASM disk group? (Choose all that apply.)
A. The au_size disk group attribute determines the size of allocation units in the disk group.
B. The allocation unit size may vary but the extent size is fixed.
C. The allocation unit size and extent size are fixed for all the disks in a disk group and cannot be changed.
D. Extent management is completely automated.
Answer: A,D
QUESTION 83:
Which are the prerequisites for performing flashback transactions on your database?
(Choose all that apply.)
A. Undo retention guarantee for the database must be configured.
B. Supplemental log must be enabled for the primary key.
C. Supplemental log must be enabled.
D. Execute permission on the DBMS_FLASHBACK package must be granted to the user.
Answer: B,C,D
解析：
参考Oracle官方文档：
https://docs.oracle.com/cd/E11882_01/appdev.112/e41502/adfns_flashback.htm#ADFNS610
Configuring Your Database for Oracle Flashback Transaction Query
To configure your database for the Oracle Flashback Transaction Query feature, you or your database administrator must:
Ensure that Oracle Database is running with version 10.0 compatibility.
Enable supplemental logging:
ALTER DATABASE ADD SUPPLEMENTAL LOG DATA;
Configuring Your Database for Flashback Transaction
To configure your database for the Flashback Transaction feature, you or your database administrator must:
With the database mounted but not open, enable ARCHIVELOG:
ALTER DATABASE ARCHIVELOG;
Open at least one archive log:
ALTER SYSTEM ARCHIVE LOG CURRENT;
If not done, enable minimal and primary key supplemental logging:
ALTER DATABASE ADD SUPPLEMENTAL LOG DATA;
ALTER DATABASE ADD SUPPLEMENTAL LOG DATA (PRIMARY KEY) COLUMNS;
If you want to track foreign key dependencies, enable foreign key supplemental logging:
ALTER DATABASE ADD SUPPLEMENTAL LOG DATA (FOREIGN KEY) COLUMNS;
Note:
If you have very many foreign key constraints, enabling foreign key supplemental logging might not be worth the performance penalty.
QUESTION 84:
Which statement is true regarding online redefinition for the migration of BasicFile LOBs to SecureFile LOBs?
A. It can be done at the table level or partition level.
B. It does not require additional storage because the operation is done online.
C. Local and global indexes are maintained automatically during the operation.
D. It cannot be done in parallel.
Answer: A
QUESTION 85:
Which three statements about performance analysis by SQL Performance Analyzer are true? (Choose three.)
A. It produces results that can be used to create the SQL plan baseline.
B. It detects changes in SQL execution plans.
C. It generates recommendations to run SQL Tuning Advisor to tune regressed SQLs.
D. The importance of SQL statements is based on the size of the objects accessed.
E. It shows only the overall impact on workload and not the net SQL impact on workload.
Answer: A,B,C
QUESTION 86:
The INV_HISTORY table is created using the command:
SQL>CREATE TABLE INV_HISTORY
(inv_no NUMBER(3),
inv_date DATE,
inv_amt NUMBER(10,2))
partition by range (inv_date)
interval (numtoyminterval(1,'month'))
(partition p0 values less than (to_date('01-01-2005','dd-mm-yyyy')),
partition p1 values less than (to_date('01-01-2006','dd-mm-yyyy')));
The following data has been inserted into the INV_HISTORY table :
INV_NO INV_DATE INV_AMT
1 30-dec-2004 1000
2 30-dec-2005 2000
3 1-feb-2006 3000
4 1-mar-2006 4000
5 1-apr-2006 5000
You would like to store the data belonging to the year 2006 in a single partition and issue the command:
SQL> ALTER TABLE inv_history MERGE PARTITIONS
FOR(TO_DATE('15-feb-2006','dd-mon-yyyy')), FOR(TO_DATE('15-apr-2006'))
INTO PARTITION sys_py;
What would be the outcome of this command?
A. It executes successfully, and the transition point is set to '15-apr-2006'.
B. It produces an error because the partitions specified for merging are not adjacent.
C. It produces an error because the date values specified in the merge do not match the date values stored in the table.
D. It executes successfully, and the transition point is set to '1-apr-2006'.
Answer: B
QUESTION 87:
You plan to have a larger moving window size for the default system-defined moving window baseline because you want to use the adaptive threshold. Which statement factors in this consideration while increasing the size of the moving window?
A. The moving window size must be less than Undo Retention.
B. The moving window size should be greater than the Automatic Workload Repository (AWR) retention period.
C. The collection level for the AWR should be set to BASIC.
D. The moving window size should be equal to or less than the Automatic Workload Repository (AWR) retention period.
Answer: D
QUESTION 88:
You issued the following command:
CREATE GLOBAL TEMPORARY TABLE admin_work_area
(startdate DATE,
enddate DATE,
class CHAR(20))
ON COMMIT DELETE ROWS
TABLESPACE tbs_t1;
An index is then created on the ADMIN_WORK_AREA temporary table.
Which two statements are true regarding the TBS_T1 tablespace in the above command?
(Choose two.)
A. It stores only the temporary table but not its indexes.
B. It must be a nondefault temporary tablespace for the database.
C. It stores both the temporary table as well as its indexes.
D. It can be a default or nondefault temporary tablespace for the database.
E. It must be the default temporary tablespace of the user who issues the command.
Answer: C,D
QUESTION 89:
Which statements are true regarding the system-defined moving window baseline in Oracle Database 11g? (Choose all that apply.)
A. It is created when the first snapshot is collected by the Automatic Workload Repository (AWR).
B. It is created by default with the window size being equal to the AWR retention time.
C. Adaptive threshold functionalities use it by default to compute statistics.
D. It does not allow you to change the moving window size.
Answer: B,C
QUESTION 90:
Which three statements correctly describe the features of the I/O calibration process?
(Choose three.)
A. Only one I/O calibration process can run at a time.
B. It automates the resource allocation for the Automated Maintenance Tasks.
C. The latency time is computed only when the TIMED_STATISTICS initialization parameter is set to TRUE.
D. It improves the performance of the performance-critical sessions while running.
E. It can be used to estimate the maximum number of I/Os and maximum latency time for the system.
Answer: A,C,E
解析：
参考Oracle官方文档;
https://docs.oracle.com/cd/B28359_01/server.111/b28274/iodesign.htm#CHDGBECA