问题
单项选择题
数据仓库通过数据转移从多个数据源中提取数据，为了解决不同数据源格式不统一的问题，需要进行 (57) 操作。
A．简单转移
B．清洗
C．集成
D．聚集和概括
答案
参考答案：B
解析：
[分析]： 构建数据仓库的重要一环就是用户从数据源抽取出所需的数据，经过数据清洗，最终按照预先定义好的数据仓库模型，将数据加载到数据仓库中去。
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数据仓库通过数据转移从多个数据源中提取数据，为了解决不同数据源格式不统一的问题，需要进行 (57) 操作。
A．简单转移
B．清洗
C．集成
D．聚集和概括
参考答案：B
解析：
[分析]： 构建数据仓库的重要一环就是用户从数据源抽取出所需的数据，经过数据清洗，最终按照预先定义好的数据仓库模型，将数据加载到数据仓库中去。
Mr. Black loved his daughter very much. Every day he spent all of his free time 1____ with her. One night, he had much work to do , 2____ couldn’t play with his daughter. In order to keep her 3____he found a map of the world in a magazine and cut it into pieces. When he 4___ , Helen came running to him and was ready to play. Mr. Black said he had 5_____ time to play right now. He told the girl to put the pieces of paper back together to a map of the world, and then they could both play. About half an hour later, Helen came to her father and said,“ Okay，it’s finished. Can we play now?” Mr. Black was surprised, saying, “That’s 6____. Let’s go and see.” And sure enough, there was the picture of the world, all put together, every 7____in its place. Mr. Black said, “That’s surprising! 8_____ did you do that?” Helen said, “It was 9____ .On the back of the page was a picture of a 10_____. When I put the man together, the whole world fell into place.”
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