單項選擇題為數(shù)據(jù)庫表創(chuàng)建索引的目的是()

A.提高查詢的檢索性能
B.創(chuàng)建唯一索引
C.與SQLServer數(shù)據(jù)檢索的速度無關(guān)
D.加快數(shù)據(jù)庫打開的速度


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你可能感興趣的試題

1.單項選擇題有關(guān)SQLSERVER 2008創(chuàng)建數(shù)據(jù)表的說法,以下正確的是()

A.數(shù)據(jù)庫對創(chuàng)建表的數(shù)量沒有限制
B.創(chuàng)建數(shù)據(jù)庫表示不能同時創(chuàng)建約束
C.創(chuàng)建數(shù)據(jù)庫表的同時創(chuàng)建主鍵,實際上是在創(chuàng)建表后對表進行修改
D.創(chuàng)建數(shù)據(jù)庫表的同時創(chuàng)建外鍵,實際上是在創(chuàng)建表后對表進行修改

2.單項選擇題在SQLServer數(shù)據(jù)庫中,HAVING和WHERE子句以及GROUPBY可以在同一SELECT語句中使用,其正確的先后順序為()

A.GROUP BY WHERE HAVING
B.WHE REGROUP BY HAVING
C.WHE REHAVING GROUP BY
D.HAVING WHERE GROUP BY

3.單項選擇題查詢student表中的所有非空email信息,以下語句正確的是()

A.Select email from student where email!=null
B.Select email from student where emailnotisnull
C.Select email from student where email<>null
D.Select email from student where emailisnotnull

5.單項選擇題一個電視經(jīng)銷商在表Tvtype中維護庫存的電視信息,下述()語句能顯示價格(iprice)最昂貴的三種電視機的信息(cDiscription)

A.select top3 cDiscription fromTvtype order by iprice asc
B.select cDiscription from Tvtype where max(iprice)>3
C.select top3 cDiscription from Tvtype order by iprice desc
D.selec tcDiscription max(iprice)from Tvtype order by iprice