单选题The SCOTT user has an index on the ITEM_DESC column of the ITEM table. As part of the year-ending task， SCOTT updates the ITEM_DESC column for most of the rows in the ITEM table. How does this change to the table affect the index？（）A An update in a lea

第1题：

An index called ORD_CUSTNAME_IX has been created on the CUSTNAME column in the ORDERS table using the following command：   SQL>CREATE INDEX ord_custname_ix ON orders（custname）；   The ORDERS table is frequently queried using the CUSTNAME column in the WHERE clause. You want to check the impact on the performance of the queries if the index is not available. You do not want the index to be dropped or rebuilt to perform this test.  Which is the most efficient method of performing this task？（）

• A、 disabling the index
• B、 making the index invisible
• C、 making the index unusable
• D、 using the MONITORING USAGE clause for the index

第2题：

You execute the following piece of code with appropriate privileges: User SCOTT has been granted theCREATE SESSION privilege and the MGR role.Which two statements are true when a session logged in as SCOTT queries the SAL column in the viewand the table?（）

• A、Data is redacted for the EMP.SAL column only if the SCOTT session does not have the MGR role set.
• B、Data is redacted for EMP.SAL column only if the SCOTT session has the MGR role set.
• C、Data is never redacted for the EMP_V.SAL column.
• D、Data is redacted for the EMP_V.SAL column only if the SCOTT session has the MGR role set.
• E、Data is redacted for the EMP_V.SAL column only if the SCOTT session does not have the MGR role set.

第3题：

You work as a database administrator for Certkiller .com. As a result of performance analysis， you created an index on theprod_namecolumn of the  Certkiller prodtable， which contains about ten thousand rows. Later， you updated a product name in the table.  How does this change affect the index？（）

• A、A leaf will be marked as invalid.
• B、An update in a leaf row takes place.
• C、The index will be updated automatically at commit.
• D、A leaf row in the index will be deleted and inserted.
• E、The index becomes invalid when you make any updates

第4题：

You are using Oracle Enterprise Manager to estimate the size of a table to be created. You have typed data regarding the column names， data types， sizes of the columns， and the projected number of rows in the table. Which additional information does the Oracle Enterprise Manager return？（）

• A、 space allocated in the tablespace
• B、 space required for the bitmap index on a column of the table
• C、 space remaining in the tablespace after creating the table
• D、 estimated value of the PCTFREE storage parameter

第5题：

You have altered a non-unique index to be invisible to determine if queries execute within an acceptable response time without using this index. Which two are possible if table updates are performed which affect the invisible index columns?（）

• A、The index remains invisible.
• B、The index is not updated by the DML statements on the indexed table.
• C、The index automatically becomes visible in order to have it updated by DML on the table.
• D、The index becomes unusable but the table is updated by the DML.
• E、The index is updated by the DML on the table.

第6题：

You are responsible for managing the database schema for an order entry application in a SQL Server 2005 database. After a design review， a member of the development staff asks you to add a new column named CommissionRate to the Product table. Because the actual commission rates for all products are not known at this time， each product has a default commission rate of 12 percent. The rate can be modified as necessary. You add the new column. You need to configure the table to assign the default value as efficiently as possible. What should you do？（）

• A、Create an INSERT trigger to assign the default value to each item in the table.
• B、Create a CHECK constraint to validate the data and to assign the default value to each item in the table.
• C、Create an UPDATE trigger to update the default value for each new item in the table.
• D、Create a DEFAULT constraint to assign the default value specifying the WITH VALUES argument.

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第13题：

As a result of performance analysis， you created an index on the prod_name column of the prod_det table， which contains about ten thousand rows. Later， you updated a product name in the table. How does this change affect the index？（）

• A、A leaf will be marked as invalid.
• B、An update in a leaf row takes place.
• C、The index will be updated automatically at commit.
• D、A leaf row in the index will be deleted and inserted.
• E、The index becomes invalid when you make any updates.

第14题：

You need to change the definition of an existing table. The COMMERCIALS table needs its DESCRIPTION column changed to hold varying length characters up to 2000 bytes. The column can currently hold 1000 bytes per value. The table contains 20000 rows. Which statement is valid?（）

• A、ALTER TABLE commercials MODIFY (description CHAR2(2000));
• B、ALTER TABLE commercials CHANGE (description CHAR2(2000));
• C、ALTER TABLE commercials CHANGE (description VARCHAR2 (2000));
• D、ALTER TABLE commercials MODIFY (description VARCHAR2 (2000));
• E、You cannot increase the size of a column if the table has rows.

第15题：

The user HR owns the EMP table. The user HR grants privileges to the user SCOTT by using this command：  SQL> GRANT SELECT，INSERT，UPDATE ON emp TO scott WITH GRANT OPTION； The user SCOTT executes this command to grant privileges to the user JIM： SQL> GRANT SELECT，INSERT，UPDATE ON hr.emp TO jim；  Now， the user HR decides to revoke privileges from JIM using this command： SQL> REVOKE SELECT，INSERT，UPDATE ON emp FROM jim； Which statement is true after HR issues the REVOKE command（）

• A、The command fails because SCOTT still has privileges.
• B、The command succeeds and privileges are revoked from JIM.
• C、The command fails because HR cannot revoke the privileges from JIM.
• D、The command succeeds and only HR has the privilege to perform the SELECT， INSERT， and UPDATEoperations on the EMP table.

第16题：

The SCOTT user has an index on the ITEM_DESC column of the ITEM table. As part of the year-ending task， SCOTT updates the ITEM_DESC column for most of the rows in the ITEM table. How does this change to the table affect the index？（）

• A、An update in a leaf row takes place.
• B、The index becomes invalid after the update.
• C、The leaf block containing the row to be updated is marked as invalid.
• D、A row in the leaf block of the index for the key value is deleted and inserted.

第17题：

You are responsible for managing the database schema for an order entry application in a SQL Server 2005 database. After a design review, a member of the development staff asks you to add a new column named CommissionRate to the Product table. Because the actual commission rates for all products are not known at this time, each product has a default commission rate of 12 percent. The rate can be modified as necessary. You add the new column. You need to configure the table to assign the default value as efficiently as possible. What should you do?（）

• A、 Create an INSERT trigger to assign the default value to each item in the table. 
• B、 Create a CHECK constraint to validate the data and to assign the default value to each item in the table. 
• C、 Create an UPDATE trigger to update the default value for each new item in the table. 
• D、 Create a DEFAULT constraint to assign the default value specifying the WITH VALUES argument.

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