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单选题Which of the following is true of an index used to support a UNIQUE constraint?（）A It must have the UNIQUE attribute.B It cannot be created explicitly by the user.C It must have the UNIQUE and CLUSTER attributes.D It must have the UNIQUE WHERE NOT NULL

题目
单选题
Which of the following is true of an index used to support a UNIQUE constraint?（）
A

It must have the UNIQUE attribute.

B

It cannot be created explicitly by the user.

C

It must have the UNIQUE and CLUSTER attributes.

D

It must have the UNIQUE WHERE NOT NULL attribute.

参考答案和解析
正确答案： D
解析： 暂无解析
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相似问题和答案

第1题：

Which of the following describe the process identifier that is used to run OSPF on a router?()

A. It is locally significant.

B. It is globally significant.

C. It is needed to identify a unique instance of an OSPF database.

D. It is an optional parameter required only if multiple OSPF processes are running on the router.

E. All routers in the same OSPF area must have the same process ID if they are to exchange routing information.


参考答案：A, C

第2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3题：

A UDT is a data type which:()

A.must contain unique values.

B.cannot be CAST to other data types.

C.is created using the CREATE DISTINCT command.

D.contains a value that was automatically calculated from values in other columns.


参考答案：C

第4题：

A UDT is a data type which:（）

  • A、must contain unique values.
  • B、cannot be CAST to other data types.
  • C、is created using the CREATE DISTINCT command.
  • D、contains a value that was automatically calculated from values in other columns.

正确答案:C

第5题：

Which of the following describe the process identifier that is used to run OSPF on a router (Choose two.)（）。

  • A、It is locally significant
  • B、It is globally significant
  • C、It is needed to identify a unique instance of an OSPF database
  • D、It is an optional parameter required only if multiple OSPF processes are running on the router
  • E、All routers in the same OSPF area must have the same process ID if they are to exchange routing information

正确答案:A,C

第6题：

Which of the following describe the process identifier that is used to run OSPF on a router (Choose two.)()。

A.It is locally significant

B.It is globally significant

C.It is needed to identify a unique instance of an OSPF database

D.It is an optional parameter required only if multiple OSPF processes are running on the router

E.All routers in the same OSPF area must have the same process ID if they are to exchange routing information


参考答案：A, C

第7题：

Which of the following describe the process identifier that is used to run OSPF on a router? (Choose two.)（）

  • A、It is locally significant.
  • B、It is globally significant.
  • C、It is needed to identify a unique instance of an OSPF database.
  • D、It is an optional parameter required only if multiple OSPF processes are running on the router.
  • E、All routers in the same OSPF area must have the same process ID if they are to exchange routing information.

正确答案:A,C

第8题：

Which of the following is true of an index used to support a UNIQUE constraint?()

A.It must have the UNIQUE attribute.

B.It cannot be created explicitly by the user.

C.It must have the UNIQUE and CLUSTER attributes.

D.It must have the UNIQUE WHERE NOT NULL attribute.


参考答案：A

第9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10题：

which one of the following accurately describes field names?（）

  • A、they must be unique in a database  
  • B、they can only be used once in a view  
  • C、they can only used once on each form  
  • D、they can be used mulriple times on a form 

正确答案:C

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