单选题A senior DBA asked you to execute the following command to improve performance: SQL> ALTER TABLE subscribe log STORAGE (BUFFER_POOL recycle); You checked the data in the SUBSCRIBE_LOG table and found that it is a large table containing one million rows

第1题：

You design a Business Intelligence （BI） solution by using SQL Server 2008. You create a SQL Server 2008 Integration Services （SSIS） package to perform an extract， transform， and load （ETL） process to load data to a DimCustomer dimension table that contains 1 million rows. Your data flow uses the following components： A SQL Destination data flow task to insert new customers An OLE DB Command transform that updates existing customers On average， 25 percent of existing customer records is updated each night. You need to reduce the amount of time required to update customer records. What should you do？（）

• A、 Modify the UPDATE statement in the OLE DB Command transform to use the PAGLOCK table hint. 
• B、 Modify the UPDATE statement in the OLE DB Command transform to use the TABLOCK table hint. 
• C、 Stage the data in the data flow. Replace the OLE DB Command transform in the data flow with an Execute SQL task in the control flow.
• D、 Stage the data in the data flow. Replace the UPDATE statement in the OLE DB Command transform with a DELETE statement followed by an INSERT statement.

第2题：

You are responsible for a data warehouse application that uses records from an external table to update one of the dimension tables periodically. The records in the external table may contain data for new rows in the dimension table， or for updates to its existing rows. Which type of SQL command would you use to transfer the data from the external table to the dimension table as efficiently as possible？（）

• A、MERGE
• B、SELECT …CROSS JOIN
• C、INSERT ALL …SELECT
• D、CREATE VIEW …CONSTRAINT

第3题：

You discover that your Recycle Bin contains two tables with the same name, MY_TABLE. You also have a table named MY_TABLE in your schema. You execute the following statement: FLASHBACK TABLE my_table TO BEFORE DROP RENAME TO my_table2; What will be the result of executing this statement?（）

• A、One of the tables is recovered from the Recycle Bin using a First In First Out (FIFO) approach.
• B、One of the tables is recovered from the Recycle Bin using a Last In First Out (LIFO) approach.
• C、Both the tables are recovered from the Recycle Bin with one table renamed to MY_TABLE2 and the other to a system-generated name.
• D、None of the tables are recovered from the Recycle Bin, and the statement returns an error.

第4题：

You execute the following command in your Certkiller .com production database to change the width of the CUST_NAME column of the CUSTOMERS table： ALTER TABLE customers  MODIFY （cust_nameVARCHAR2 （40）） /  When you execute the command， it displays the following error message：  ERROR at line 1：  ORA-00054： resource busy and acquire with NOWAIT specified  What could be the reason for the error message？（）

• A、The database instance is not available.
• B、The ALTER TABLE command does not have WAIT option
• C、The table or a row in the table is currently locked by another user session.
• D、The database instance is busy processing other user sessions commands.
• E、The CUSTOMERS table has no long running query active at the time when this request is made.
• F、The server process executing the ALTER TABLE command is busy with another command execution

第5题：

One of the users in the PROD database， Adams， complains that his update on the table， TRANS， is taking an unusually long time to complete. You find that the table gets locked by another database user before Adams starts his transactions， and you are unable to contact the user holding the table lock. As Adams is updating some crucial rows in the table， he should get the highest priority. Which method would you use to overcome this problem？（）

• A、execute the command， ALTER SESSION KILL ..， to kill the blocking session
• B、execute the DBMS_SESSION.KILL_SESSION procedure to kill the blocking session
• C、execute the command， ALTER SYSTEM KILL SESSION ..， to kill the blocking session
• D、execute the command， ALTER SESSION UNLOCK ..， to release the lock for the blocking session
• E、execute the command， ALTER SYSTEM UNLOCK SESSION ..， to release the lock for the blocking session

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第13题：

In your test database， you have created the ORDERS table as an index/x7forganized table （IOT）. To facilitate faster querying， you have created a mapping table and a bitmap index on the ORDER_FILLED column. You observe that the query performance degrades when users perform a large volume of transactions.  While investigating the reason， you find that the mapping table segment is fragmented， leading to poor performance. Which option would you use to defragment the mapping table without affecting the original table data？（）

• A、export and import the mapping table
• B、drop and re­create the mapping table
• C、truncate the mapping table and reinsert the values
• D、use the ALTER TABLE .. REBUILD command to defragment the mapping table

第14题：

Before a Flashback Table operation, you execute the following command: ALTER TABLE employees ENABLE ROW MOVEMENT; Why would you need this to be executed?（）

• A、Because row IDs may change during the flashback operation
• B、Because the object number changes after the flashback operation
• C、Because the rows are retrieved from the recycle bin during the flashback operation
• D、Because the table is moved forward and back to a temporary during the flashback opertion

第15题：

A senior DBA asked you to execute the following command to improve performance: SQL> ALTER TABLE subscribe log STORAGE (BUFFER_POOL recycle); You checked the data in the SUBSCRIBE_LOG table and found that it is a large table containing one million rows. What could be a reason for this recommendation?（）

• A、The keep pool is not configured.
• B、Automatic Workarea Management is not configured.
• C、Automatic Shared Memory Management is not enabled.
• D、The data blocks in the SUBSCRIBE_LOG table are rarely accessed.
• E、All the queries on the SUBSCRIBE_LOG table are rewritten to a materialized view

第16题：

You issued the following command to drop the PRODUCTS table: SQL> DROP TABLE products; What is the implication of this command?（）

• A、All data along with the table structure is deleted 
• B、The pending transaction in the session is committed 
• C、All indexes on the table will remain but they are invalidated 
• D、All views and synonyms will remain but they are invalidated 
• E、All data in the table are deleted but the table structure will remain

第17题：

You have a very large table that your users access frequently. Which of the following advisors will recommend any indexes to improve the performance of queries against this table?（）

• A、The Automatic Memory Manager (AMM)
• B、The SQL Tuning Advisor
• C、The Segment Advisor
• D、The SQL Access Advisor

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