问题 单项选择题

设有关系SC(SNO,CNO,GRADE),其中SNO、CNO分别表示学号和课程号(两者均为字符型),GRADE表示成绩(数值型)。若要把学号为"S101"的同学,选修课程号为 "C11",成绩为98分的记录插入到表SC中,正确的语句是【 】。

A.INSERT INTO SC(SNO,CNO,GRADE)VALUES(′S1 01′,′C11′,′98′)

B.INSERT INTO SC(SNO,CNO,GRADE)VALUES(S101,C11,98)

C.INSERT(′S101′,′C11′,′98′)INTO SC

D.INSERT INTO SC VALUES(′S101′,′C11′,98)

答案

参考答案:D

解析:插入命令:INSERT INTO<表名>[(<属性列1>,<属性列2>…)]VALUES(eExpression1[eExpression2,…]),若插入的是完整的记录时,可以省略<属性列1>,<属性列2>…;另外,SNO、CNO为字符型,故其属性值需要加引号,数值型数据不需要加引号。

填空题



In the early 1970’s, Citibank of New York City became one of the first financial institutions to install ATM’s on a large scale. Since then, the (1) of automated teller machines has increased dramatically. At the time, the bank hoped (2) their operating costs by replacing human tellers with machines. Little did they (3) that the cash machines would become so successful. However, as more banks added (4) automated service through ATM’s, the machines mushroomed all over the world.
To use an ATM, all you need is a (5) issued by your bank. Your bank may also (6) through a credit card, such as MasterCard or Visa. To begin a (7) , you need to insert the card into an ATM and punch in a personal identification number on the (8) . The personal ID number may consist of (9) and can prevent anyone from using the card.
The ATM next flashes instructions on its (10) for carrying out transaction. To get cash, for example, you are instructed to (11) that indicate whether the money should be withdrawn from a checking or a savings account and the (12) . This request is then displayed on the screen. After you press a button to (13) that the information is correct, the ATM goes to (14) .
How safe, you may ask, is banking by ATM The (15) is meant to prevent anyone, no matter who you are, from using a cash card (16) . If you enter the wrong ID number for a card, a message on the screen will (17) . If you fail to produce the correct number for three times, most machines will (18) .As another precaution against (19) , the bank generally limits the amount that may be withdrawn by cash card (20) , say, to $ 200.

单项选择题