问题
单项选择题
数据独立性是数据库技术的重要特点之一。所谓数据独立性是指
A．数据与程序独立存放
B．不同的数据被存放在不同的文件中
C．不同的数据只能被对应的应用程序所使用
D．以上三种说法都不对
答案
参考答案：D
解析： 数据独立性是数据与程序间的互不依赖性，即数据库中数据独立于应用程序而不依赖于应用程序。所以选项A，选项B和选项C都不正确。
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数据独立性是数据库技术的重要特点之一。所谓数据独立性是指
A．数据与程序独立存放
B．不同的数据被存放在不同的文件中
C．不同的数据只能被对应的应用程序所使用
D．以上三种说法都不对
参考答案：D
解析： 数据独立性是数据与程序间的互不依赖性，即数据库中数据独立于应用程序而不依赖于应用程序。所以选项A，选项B和选项C都不正确。
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| One day a professor was crossing a river in a boat. To pass the time he started talking to the boatman. He told him his several 1 in education. The boatman was 2 listening to the professor 3 he didn't understand what he was saying to him. After having said many things, the professor got 4 of speaking. He asked the boatman,"Now tell me something about you. Have you 5 studied the science of grammar?" "No, I haven't.""Then you've wasted half of your 6 . How much education have you got?""I'm not educated much. I 7 in my 5th grade, and since then I've been sailing the boat." 8 this, the professor got silent. The boatman wasn't happy with the 9 of the professor, but remained cool on his face. Soon the black clouds 10 flying low across the sky, and a storm moved in as they sailed across the water. They were 11 in the storm, and the boat got out of 12 . Fearing that the boat would capsize (倾覆), the boatman 13 at the professor,"Professor, do you know how to swim?" The professor replied with contempt (蔑视), "I never 14 my time with such a hobby." The boatman cried,"The boat is going to 15 in this water. It is you who have wasted your life by not learning to 16 , because you're going to drown (淹死) in this water." And he 17 into the water to save himself. It's 18 how we spend our lives and what we value. Only that education is valuable which is useful on the occasion. The professor was proud of his 19 , while swimming was more valuable when crossing the water. 20 had their own fields of specialization(专门领域). Jobs differ by post, not social standing. | ||||
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