In your test database, you have created the ORDERS table as 

题目
单选题
In your test database, you have created the ORDERS table as an index-organized 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 degrees 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 re-create the mapping table.

C

 Truncate the mapping table and reinsert the values.

D

 Use the ALTER TABLE .. REBUILD command to defragment the mapping table.

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相似问题和答案

第1题:

While designing your database, you have created the EMPLOYEES table as an index-organized table (IOT). You want to create a bitmap index on the JOB_ID column to make queries faster. Which task must have been completed so that you are able to create the bitmap index?() 

  • A、A primary key must have been created.
  • B、A mapping table must have been created.
  • C、An overflow tablespace must have been specified.
  • D、The PCTTHRESHOLD option must have been specified.

正确答案:B

第2题:

Your company uses a SQL Server 2005 database. This database contains a trigger named trg_InsertOrders, which fires when order data is inserted into the Orders table. The trigger is responsible for ensuring that a customer exists in the Customers table before data is inserted into the Orders table. You need to configure the trigger to prevent it from firing during the data import process. You must accomplish this goal while using the least amount of administrative effort.  Which two Transact-SQL statements can you use to achieve this goal?()

  • A、 ALTER TABLE OrdersDISABLE TRIGGER trg_InsertOrders 
  • B、 DROP TRIGGER trg_InsertOrders 
  • C、 DISABLE TRIGGER trg_InsertOrders ON Orders 
  • D、 ALTER TRIGGER trg_InsertOrders  ON Orders NOT FOR REPLICATION 
  • E、 sp_settriggerorder@triggername= 'trg_InsertOrders', @order='None'

正确答案:A,C

第3题:

Which describes the default behavior when you create a table? ()

A. The table is accessible to all users.

B. Tables are created in the public schema.

C. Tables are created in your schema.

D. Tables are created in the DBA schema.

E. You must specify the schema when the table is created.


参考答案:C

第4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

正确答案:B

第5题:

While designing your database, you have created the EMPLOYEEStable as an index-organized (IOT). You want to create a bitmap index on the JOD_IDcolumn to make queries faster. Which task must have been completed so that you are able to create the bitmap index?()

  • A、 A primary key must have been created.
  • B、 A mapping table must have been created.
  • C、 An overflow tablespace must have been specified.
  • D、 The PCTTHRESHOLD option must have been specified.

正确答案:B

第6题:

The database administrator of your company created a public synonym called HR for the HUMAN_RESOURCES table of the GENERAL schema, because many users frequently use this table. As a user of the database, you created a table called HR in your schema. What happens when you execute this query? SELECT * FROM HR; ()

  • A、You obtain the results retrieved from the public synonym HR created by the database administrator.
  • B、You obtain the results retrieved from the HR table that belongs to your schema.
  • C、You get an error message because you cannot retrieve from a table that has the same name as a public synonym.
  • D、You obtain the results retrieved from both the public synonym HR and the HR table that belongs to your schema, as a Cartesian product.
  • E、You obtain the results retrieved from both the public synonym HR and the HR table that belongs to your schema, as a FULL JOIN.

正确答案:B

第7题:

You work as a database administrator for Certkiller .com. In your transaction application, you have scheduled a job to update the optimizer statistics at05:00 pm every Friday. The job has successfully completed. Which three pieces of information would you check to confirm that the statistics have been collected?()

  • A、Average row size
  • B、Last analyzed date
  • C、Size of table in bytes
  • D、Size of table in database blocks
  • E、Number of free blocks in the free list
  • F、Number of extents present in the table.

正确答案:A,B,D

第8题:

While designing your database, you have created the EMPLOYEES table as an index/x7forganized table (IOT). You want to create a bitmap index on the JOB_ID column to make queries faster. Which task must have been completed so that you are able to create the bitmap index?()

  • A、A primary key must have been created.
  • B、A mapping table must have been created.
  • C、An overflow tablespace must have been specified.
  • D、The PCTTHRESHOLD option must have been specified.

正确答案:B

第9题:

A table was just created on your Oracle database with six extents allocated to it. Which of the following factors most likely caused the table to have so many extents allocated?()

  • A、The value for MINEXTENTS setting 
  • B、The value for PCTINCREASE setting 
  • C、The value for MAXEXTENTS setting 
  • D、By default, Oracle allocates six extents to all database objects

正确答案:A

第10题:

Flashback Database is enabled in your Oracle 10g database. One of your database users erroneously purged an important table residing in his schema. The table was purged sometime between 10:00 P.M. and 10:30 P.M. The next day, you decide to flash back the database. Before you flash back the database, you want to ensure that you have all the necessary flashback data. Which dynamic performance view must you use to determine whether you have the required flashback data to recover the purged table?()

  • A、 V$DATABASE
  • B、 V$UNDOSTAT
  • C、 V$FLASHBACK_DATABASE_LOG
  • D、 V$FLASHBACK_DATABASE_STAT

正确答案:C

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