问题 单项选择题

以下关于主关键字的说法,错误的是 ______。

A) 使用自动编号是创建主关键字最简单的方法
B) 作为主关健字的字段中允许出现Null值
C) 作为主关键宇的字段中不允许出现重复值
D) 不能确定任何单字段的值得惟一性时,可以将两个或更多的字段组合成为主关键字

答案

参考答案:B

解析: 数据库和表的摹本操作/表的建立
[评析] 为了使保存在不同表中的数据产生联系,Access数据库中的每个表必须有一个字段能惟一标识每条记录,这个字段就是主关键字。主关键字可以是一个字段,也可以是一组字段。为确保主关键字段值的惟一性,Access不允许在主关键字字段中存入重复值和空值。自动编号字段是在每次向表中添加新记录时,Access会自动插入惟一顺序号。库中若未设置其它主关键字时,在保存表时会提示创建主键,单击“是”按钮,Access为新建的表创建一个“自动编号”字段作为主关键字。

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完形填空 (共20小题;每小题1.5分,满分30分)

Travel in most of Europe is easy. An agreement between the 15 European Union countries in 1995 means that citizens from most European countries can travel across borders without needing a visa.

Each of the 12 countries that has   36   its own currency (货币) to accept the euro has its own   37  . So how have these countries been able to   38  ? And how has each country prepared for the birth of this new currency? Firstly, many people in Europe,  39  in west Europe, speak English. The European Convention on Human Rights says that all people have a  40  to learn and use their traditional language.

But at the European Central Bank in Frankfurt, Germany, the official language for all business is   41  . And every European country requires students to study English for many years at   42  . Other languages may be offered, too. But English is a   43   .

"If I meet someone, I try Spanish. Then I try   44  . And if it's not   45   , I say "Hello". That' s the signal, and we communicate no matter what country we come from." Said Maria Ortega, a ski instructor in the Pyrenees,   46   French and Spanish are mainly used.

Each country has its own   47   culture. Though the French may be famous for their 1,000 types of cheese and the Greeks are known to  48   olive oil on everything, most people in Europe like  49  strong coffee on their breakfast table. Another drink is held  50  throughout the continent. Europe's vineyards(葡萄园) may be famous, but the real drink of Europe is   51  . Europeans consume tons of it.

Football, of course, also helps to    52    all of Europe. Many fans are obsessed (着迷) with   53   and with international stars. David Beckham, of England' s Manchester United, is a hero to Europeans in the same   54   that Michael Jordan is to   55   .

36. A. given up                    B. ended up          C. agreed with                   D. started with

37. A. money                B. right                             C. border                          D. culture

38. A. meet                          B. unite                            C. travel                            D. accept

39. A. specially         B. generally             C. particularly                  D. normally

40. A. chance                 B. right                             C. wish                              D. place

41. A. French                  B. German                 C. English                     D. Spanish

42. A. school                  B. work                             C. home                            D. table

43. A. subject                 B. tool                         C. need                          D. must

44. A. English                 B. French                    C. German                  D. Greek

45. A. listening                    B. spoken                   C. working                   D. heard

46. A. as                          B. where                     C. since                             D. whose

47. A. food                           B. art                          C. drink                              D. life

48. A. add                             B. spread                    C. spend                            D. put

49. A. a kind of          B. a lot of                  C. a cup of                D. a taste of

50. A. in common       B. in general                C. in need                     D. in special

51. A. beer                           B. wine                             C. coffee                           D. soup

52. A. attract            B. tie                                C. play                          D. watch

53. A. opera                         B. bread                           C. music                            D. football

54. A. direction                   B. level                             C. way                          D. game

55. A. basketballers           B. British              C. athletes   D. Americans