J.Manin将计算机的数据环境分为四种类型，按由高到低的层次依次为（）
A.应用数据库、主题数据库、信息检索系统、数据文件
B.信息检索系统、主题数据库、应用数据库、数据文件’
C.信息检索系统、应用数据库、主题数据库、数据文件
D.主题数据库、应用数据库、信息检索系统、数据文件
参考答案：B
解析：
J.Martin清晰地区分了计算机的4类数据环境，认为一个高效率和高性能的企业应该基本具有4类数据环境作为基础，由低到高的层次依次为：信息检索系统、主题数据库、应用数据库和数据文件。
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| I was cleaning out an old box when an old card caught my eye: Queen City Casket Company. "What is it?" I 1 . I turned it over. There, in faded (已褪色的) ink, was a hand-scrawled (手写的) 2 . Immediately my mind traveled back many years.  I was nine years old, 3 down the cold, wet streets of Springfield, with a bag of 4 on my shoulder. On my 5 that day, I came to that Company finally, whose owner, Mr. Rader, had always 6 me there to ask his workers whether they 7 any magazines.  Shaking off the 8 like a wet dog, I entered Mr. Rader's office. After a quick glance he 9 me over to the fire-place. Noticing the hole in the top of my 10 , he said, "Come with me!", pulling me into his pick-up truck. We pulled to a stop before a shoe shop. Inside, a salesman 11 me with the finest pair of Oxfords I had ever 12 . I felt about 10 feet tall when I 13 in them. "We'd like a air of new 14 , too." Mr. Rader said. Back in his office, Mr. Rader took out a 15 , wrote something on it, and handed it to me. With 16 eyes, I read, "Do to others as you would have them do to you." He said affectionately (深情地), "Jimmy, I want you to 17 I love you." I said good-bye, and for the first time I 18 a flicker (闪烁) of hope that somehow things would be all right. With people like Mr. Rader in the world, there was hope, kindness and 19 and that  would always make a 20 .  | ||||
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