当前位置:考试网  > 试卷库  > 计算机类  > 等级考试  > 计算机二级  >  什么是数据库的安全性?
试题预览

什么是数据库的安全性?

查看答案
收藏
纠错
正确答案:

数据库的安全性是指保护数据库以防止不合法的使用所造成的数据泄露、更改或破坏。

答案解析:

暂无解析

你可能感兴趣的试题

数据库系统的三级模式结构是 ______。

查看当前正在使用的工作数据库名称的语句是 ______。

部门表 tb_dept 的定义如下:下列说法中正确的是 ______。

CREATE TABLE tb_dept(

deptno CHAR(2) primary key ,

dname CHAR(20) Not null ,

manager CHAR(12),

telephone CHAR(15)

);

下列关于空值的描述中,正确的是 ______。

以下关于触发器的叙述中,正确的是 ______。

热门试题 更多>
试题分类: 社区工作人员
练习次数:0次
试题分类: 安全员
练习次数:0次
Passage 3 Questions 11 to 15 are based on the following passage: The cowboy is the hero of many movies,. He is, even today, a symbol of courage and adventure. But what was the life of the cowboy really like? The cowboy’s job is clear from the word cowboy. Cowboy were men who took care of cows and other cattle. The cattle were in the West and in Texas. People in the cities of the East wanted beef these cattle. Trains could take the cattle east. But first the cattle had to get to the trains. Part of the cowboy’s job was to take the cattle hundreds of miles to the railroad town. The trips were called cattle drivers. A cattle drive usually took several months. Cowboys rode for sixteen hours a day. Because they rode so much, each cowboy brought along about eight horses. A cowboy changed horses several times each day. The cowboys had to make sure that cattle arrived safely. Before starting on a drive, the cowboys branded the cattle. They burned a mark on the cattle to show who they belonged to. But these marks didn’t stop rustlers, or cattle thieves. Cowboys had to protect the cattle from rustlers. Rustlers made the dangerous trip even more dangerous. Even though their work was very difficult and dangerous, cowboys did not earn much money. They were paid badly. Yet cowboys liked their way of life. They lived in a wild and open country. They lived a life of adventure and freedom. 11. A cowboy is a symbol of . A. courage and adventure B. a hard life and big pay C. movies in the past D. cows and other cattle 12. The cowboys’ job was . A. to be a hero in real life B. to be a hero of the movie C. to take care of cattle D. to be a dangerous rustler 13. During a cattle driver, cowboys took a group of cows from a wild and open country to . A. the West states and Texas B. the cities of the East States C. the people who eat beef in cities D. the railroad towns hundred miles away 14. On their way of cattle drivers, the cowboys protected the cattle by . A. burning a mark on their cows B. keeping an eye on cattle thieves C. making the trip more dangerous D. looking after eight cows each person 15. Cowboys enjoyed themselves because . A. they liked their way of life B. they made a lot of money C. they had a vary difficult job D. they were heroes in movies
试题分类: 大学英语四级
练习次数:1次
The food we eat seems to have profound effects on our health. Although science has made enormous steps in making food more fit to eat, it has , atthe same time, made many foods unfit to eat. Some research has shown that perhaps eighty percent of cancer is related to the diet as well, especially cancer the colon . Different cultures are more prone to contract certain illnesses because of the food that is characteristic in these cultures. That food related to llness is not a new discovery. In 1945 , government researchers realized that itrates and nitrites, commonly used to preserve color in meats, and other food dditives, caused cancer. Yet, these carcinogenic additives remain in our food, nd it becomes more difficult all the time to know which things on the pack ging labels of processed food are helpful or harmful.The additives which we eat are not all so direct. Farmers often give penicillin to beef and poultry, and because of this, penicillin has been found in the milk of treated cows. Sometimes similar drugs are administered to animals not for medicinal purposes, but for financial reasons. The farmers are simply trying to fatten the animals in order to obtain a higher price on the market. Although the Food and Drug Administration (FDA) has tried repeatedly to controlthese procedures, the practices continue. 48. What is the main topic of the passage? A. Food and our health B Food and additives C. Food and cancer D Food and culture 49 All of the following statements are true EXCEPT_______. A Forty percent of cancer is caused by problems related to food. B Researchers have known about the potential danger of food additivesfor many years C. We eat some of the food additives directly and some indirectly D Drugs are always given to animals for medicinal purposes 50. Why do farmers give drugs to their animals? A. to speed up the growth of animals B To make theanimals fatter C to make the animals ’ meat fit to eat D To make the animals’ meat rich in nutrients 51. It can be inferred from the passage that_________. A scientist have made all the food fit to eat B only in recent years have people found that the food is related to one’s illness C all kinds of cancer are related to the diet D some additives are harmful to our health 52. The word “ this ”in the second sentence of paragraph 2 most probablyrefers to __________. A farmer B penicillin C beef and poultry D the fact that farmers often give penicillin to a beef
试题分类: 大学英语三级
练习次数:4次
Part I Reading Comprehension Directions: In this part there are four passages. Each passage is followed by four comprehension questions. Read the passage and answer the questions. Then mark your answer on the Answer Sheet. Passage 1 Questions 1 to 5 are based on the following passage: Ask three people to look the same window at a busy street corner and tell you what they see. Chances are you will receive three different answers. Each person sees the same scene, but each perceives something different about it. Perceiving goes on in our minds. Of the three people who look out the window, one may say that he sees a policeman giving a motorist a ticket. Another may say that he sees a rush-hour traffic jam at the intersection. The third may tell you that he sees a woman trying to cross the street with four children in tow. For perception is the mind’s interpretation of what the senses—in this case our eyes—tell us. Many psychologists today are working to try to determine just how a person experiences or perceives the world around him. Using a scientific approach, these psychologists set up experiments in which they can control all of the factors. By measuring and charting the results of many experiments, they are trying to find out what makes different people perceive totally different things about the same scene. 1. Seeing and perceiving are . A. the same action B. two separate actions C. two actions carried on entirely by eyes D. several actions that take place at different times 2. Perceiving is an action that takes place . A. in our eyes B. only when we think very hard about something C. only under the direction of a psychologist D. in every person’s mind 3. People perceive different things about the same scene because . A. they see different things B. some have better eyesight C. they cannot agree about things D. none of these 4. Which of the following is implied but not stated in the passage? A. Psychologists do not yet know people see. B. The experiments in which all factors are controlled are better. C. The study of perception is going on now. D. Perception does not involve psychological factors. 5. The best title for this selection is . A. How We See B. Learning about Our Minds through Science C. What Psychologists Perceive D. How to Because an Experimental Psychologist
试题分类: 大学英语六级
练习次数:2次
试题分类: 资料员
练习次数:0次
试题分类: 资料员
练习次数:0次
扫一扫,手机做题