问题 单项选择题

某公司把数据库管理系统(DBMS)用作数据存放处,而该数据库管理系统(DBMS)反过来又支持一些终端用户应用第四代编程语言创建开发的应用程序。其中的有些程序对数据库进行升级。与数据库完整性相关的最为重要的控制措施是:()

A.终端用户在访问数据库之前必须将其只读应用程序提交信息系统部门批准。

B.已建立同时升级控制措施。

C.终端用户应用程序先在个人计算机上得到开发,再在主机上进行实施。

D.已采纳等级数据库模型,以便同时服务于多个用户。

答案

参考答案:B

解析:

A.不正确,参照题解B。

B.正确。实时控制是管理两个或者多个程序需要同时使用同一个文件或者数据库的情况。它们可以保护数据的完整性。终端用户计算使得用户不需要数据处理批准,包括使用大型主机数据库的终端用户程序。第四代语言可以有效地在主机结构中开发和运行,主机和微机在这方面的区别不大。关系数据库虽然流行,但是不需要支持多用户计算。

C.不正确,参照题解B。

D.不正确,参照题解B。

填空题
阅读理解

There is an English saying:“1._________.” Until recently, few people took the saying seriously. Now, however, doctors have begun to look into laughter and the effects it has on the human body. 2. _________.

Tests were carried out to study the effects of laughter on the body. People watched funny films while doctors checked their hearts, blood pressure, breathing and muscles. It was found that laughter has similar effects to physical exercise. 3.__________. If laughter exercises the body, it must be beneficial.

Other tests have shown that laughter appears to be able to reduce the effect of pain on the body. In one experiment doctors produced pain in groups of students who listened to different radio programs. The group that tolerated(忍耐) the pain for the longest time was the group which listened to a funny program. 4._________.

5.__________. They have found that even if their patients do not really feel like laughing , making them smile is enough to produce beneficial effects similar to those caused by laughter.

A.Laughter can prolong one’s life.

B.As a result of these discoveries, some doctors in the United States now hold laughter clinics in which they help to improve their patients’ condition by encouraging them to laugh.

C.The reason why laughter can reduce pain seems to be that it helps to produce a kind of chemicals in the brain which diminish both stress and pain.

D.It increases blood pressure, the heart beating and breathing; it also works several groups of muscles in the face, the stomach and even the feet.E. Although laughter helps cure the disease, doctors still can not put this theory into clinic practice.

F. Laughter is the best medicine.

G.They have found that laughter really can improve people’s health.