问题 单项选择题

在关系数据库中,视图是三级模式结构中的

A.内模式

B.模式

C.存储模式

D.外模式

答案

参考答案:D

解析:[命题目的] 本题主要考查数据库系统的三级模式体系结构。 [解题要点] 在数据库系统的三级模式体系结构中,外模式也称子模式或用户模式,指数据库用户能够看见和使用的局部数据的逻辑结构和特征描述,是数据库用户的数据视图,是与某一应用有关的数据的逻辑表示。模式也称逻辑模式,是数据库中全体数据的逻辑结构和特征的描述,是所有用户的公共数据视图。内模式也称存储模式,是数据物理结构和存储方式的描述,是数据在数据库内部的表示方式。 [考点链接] 模式的概念、三级模式结构、数据库的二级映像。

选择题
阅读理解

阅读理解。

     Ballet is a precise and beautiful form of dancing that is performed in a theatre. A kind of ballet first appeared

in Italy in the 1400s, but ballet as it is danced today began in France. During the reign of King Louis XIV, in the

1600s, it was officially recognized as a form of art. The French Royal Academy of Dance was founded in 1661

to promote ballet.

     Traditional, or classical, ballet follows strict rules and traditions. There are standard positions for the arms,

legs and hands, and special movements that make the dance flow smoothly.

     Classical ballet uses orchestras (交响乐团), fine scenery and splendid costumes. Many ballets tell a story,

but the dancers do not speak any words. They act out the story, using their bodies. The person who arranges

the dance movements is called the choreographer (舞蹈指导).

     Some ballets are very famous. They have been danced for many years. Giselle, a story of a tragic young

village girl who dies in love-stricken grief, was first performed in 1841. Two other long-time favourites are

Swan Lake and Sleeping Beauty. These two ballets are as famous for their music as for their dancing.

     Modern ballets often look very different from classical ones. They include freer, more modern dance steps.

Sometimes, instead of telling a story, they dwell on certain moods or themes. Special effects may be produced

with lighting, rather than scenery.

1. Ballet first turned up in _____ and it was officially thought of as a form of art in _____. [ ]

A. Italy in the 1600s; in France in 1400

B. Italy in the 1400s; in France in 1400

C. Italy in the 1400s; in France in 1600

D. Italy in the 1600s; in France in 1600

2. Which statement is not true according to the passage? [ ]

A. Classical ballet follows strict rules and traditions.

B. Many ballets tell a story, and the dancers sometimes need to speak on the stage.

C. Many ballets tell a story, but the dancers do not speak any words.

D. The ballets always use their bodies to act out the story.

3. _____ are as famous for their music as for their dancing. [ ]

A. Swan Lake and Giselle

B. Sleeping Beauty and Swan Lake

B. Sleeping Beauty and Giselle

D. Traditional and modern ballets

4. The underlined phrase "dwell on" in the last paragraph might mean "_____". [ ]

A. tell sth. in detail

B. live in

C. live on

D. tell sth. in general