在数据库设计的四个阶段中，为关系模式选择存取方法应该是在______阶段。
A．需求分析
B．概念设计
C．逻辑设计
D．物理设计
参考答案：D
解析： 需求分析阶段是分析用户的需求，显然不属于这个阶段，由此可以排除选项A．概念设计是将需求分析得到的用户需求抽象为信息结构及概念模型的过程，涉及不到数据的存取，所以选项D错误。逻辑设计是在概念设计的基础上将E-R图转换成数据库管理系统的逻辑数据模型表示的逻辑模式，也不涉及存取问题，选项C也不对。答案为D。
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| I was woken up at 1 am. My roommate stood at the door with a tall man. "Please let him in," she told me. "He's been__1__out of his apartment. " She had seen him__2__in the snowy night and immediately asked him to__3__at our place. The man was a law student. He was doing his__4__in the library which closed at 11 pm when he __5__he had left his keys in his house. To tell the truth, I had never had a(n)__6__sleep in my house before. My roommate and I were both__7__than one metre sixty and we had been asked "not to__8__to a man whom you don' t know" since we were kids. Not to mention we were in a__9__city that we had stayed in less than a month. And here we were soon giving the man my blanket and pillows. He__10__our hospitality (盛情) with unwillingness__11__soon as dawn broke he went back to his apartment. The next day he came to our house__12__, telling us he owed us a big meal for not letting him be__13__in the cold night. He gave us a beautiful card reading, "Thank you so much. Your actions were so__14__He cooked us a wonderful "thank you" dinner__15__ which he told us about his life. He told us how he was completely__16__by our concern for others. I learnt a lot that evening. As he told us how he once__17__a homeless man home to have Christmas dinner with his family, a feeling of warmth rose in my__18__. My roommate taught me a huge lesson: Let go of your__19__, always leave the door of your__20__open and you can never go wrong. | |||
| ( )1.A. driven ( )2.A. shaking ( )3.A. sleep ( )4.A. show ( )5.A. knew ( )6.A. stranger ( )7.A. taller ( )8.A. go ( )9.A. modern ( )10.A. appreciated ( )11.A. and ( )12.A. crying ( )13.A. thrown ( )14.A. common ( )15.A. during ( )16.A. interested ( )17.A. called ( )18.A. heart ( )19.A. anger ( )20.A. kindness | B. made B. walking B. eat B. homework B. saw B. adult B. more B. speak B. new B. experienced B. but B. laughing B. hurt B. great B. for B. touched B. left B. body B. care B. apartment | C. taken C. running C. wait C. speech C. found C. student C. less C. listen C. big C. refused C. though C. smiling C. caught C. honest C. about C. surprised C. turned C. mind C. tear C. thoughts | D. locked D. watching D. study D. labour D. heard D. roommate D. smaller D. relate D. faraway D. accepted D. for D. shouting D. frozen D. hard D. in D. puzzled D. brought D. head D. shyness D. place |