2022年上半年（上午）《数据库系统工程师》真题-名校题库网

单选题

Corporate decision makers require access to information from multiple such sources. Seting up queries on individual sources is both cumbersome and（ 71 ）. Moreover, the sources of data may store only current data, whereas decision makers may need access to（ 72 ）dataas well. A data warehouse is a repository（or archive）of information gathered from multiple sources, stored under a unified schema, at a（ 73 ）site. Once gathered, the data are stored for a long time, permitting access to historical data. Thus, data warehouses provide the user with a single consolidated（ 74 ）to data, making decision-support queries easier to write. Moreover, by accessing information for decision support from a data warehouse, the decision maker ensures that online transaction- processing systems are not（ 75 ）by the decision-supportworkdoad.

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正确答案：B

本题解析：

企业决策者需要从多个此类来源获取信息。在单个源上设置查询既繁琐又低效。此外，数据源可能只存储当前数据，而决策者可能也需要访问过去的数据。数据仓库是从多个来源收集的信息的存储库（或归档），存储在统一的模式下，位于过去的站点。一旦收集到数据，数据就会被长期存储，从而允许访问历史数据。因此，数据仓库为用户提供了一个统一的过去数据，使决策支持查询更容易编写。此外，通过从数据仓库访问决策支持信息，决策者可以确保在线事务处理系统不受决策支持工作负载的影响。

单选题

Corporate decision makers require access to information from multiple such sources. Seting up queries on individual sources is both cumbersome and（ 71 ）. Moreover, the sources of data may store only current data, whereas decision makers may need access to（ 72 ）dataas well. A data warehouse is a repository（or archive）of information gathered from multiple sources, stored under a unified schema, at a（ 73 ）site. Once gathered, the data are stored for a long time, permitting access to historical data. Thus, data warehouses provide the user with a single consolidated（ 74 ）to data, making decision-support queries easier to write. Moreover, by accessing information for decision support from a data warehouse, the decision maker ensures that online transaction- processing systems are not（ 75 ）by the decision-supportworkdoad.

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正确答案：D

本题解析：暂无解析

单选题

Corporate decision makers require access to information from multiple such sources. Seting up queries on individual sources is both cumbersome and（ 71 ）. Moreover, the sources of data may store only current data, whereas decision makers may need access to（ 72 ）dataas well. A data warehouse is a repository（or archive）of information gathered from multiple sources, stored under a unified schema, at a（ 73 ）site. Once gathered, the data are stored for a long time, permitting access to historical data. Thus, data warehouses provide the user with a single consolidated（ 74 ）to data, making decision-support queries easier to write. Moreover, by accessing information for decision support from a data warehouse, the decision maker ensures that online transaction- processing systems are not（ 75 ）by the decision-supportworkdoad.

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正确答案：A

本题解析：暂无解析

单选题

Corporate decision makers require access to information from multiple such sources. Seting up queries on individual sources is both cumbersome and（ 71 ）. Moreover, the sources of data may store only current data, whereas decision makers may need access to（ 72 ）dataas well. A data warehouse is a repository（or archive）of information gathered from multiple sources, stored under a unified schema, at a（ 73 ）site. Once gathered, the data are stored for a long time, permitting access to historical data. Thus, data warehouses provide the user with a single consolidated（ 74 ）to data, making decision-support queries easier to write. Moreover, by accessing information for decision support from a data warehouse, the decision maker ensures that online transaction- processing systems are not（ 75 ）by the decision-supportworkdoad.

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正确答案：B

本题解析：暂无解析

单选题

Corporate decision makers require access to information from multiple such sources. Seting up queries on individual sources is both cumbersome and（ 71 ）. Moreover, the sources of data may store only current data, whereas decision makers may need access to（ 72 ）dataas well. A data warehouse is a repository（or archive）of information gathered from multiple sources, stored under a unified schema, at a（ 73 ）site. Once gathered, the data are stored for a long time, permitting access to historical data. Thus, data warehouses provide the user with a single consolidated（ 74 ）to data, making decision-support queries easier to write. Moreover, by accessing information for decision support from a data warehouse, the decision maker ensures that online transaction- processing systems are not（ 75 ）by the decision-supportworkdoad.

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正确答案：A

本题解析：暂无解析

单选题

以下关于MapReduce技术的说法中，不正确的是（　　）。

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正确答案：B

本题解析：

MapReduce的计算过程分解为两个主要阶段：Map阶段和Reducel阶段，在同等硬件条件下，MapReduce的性能远低于并行数据库。MapReduce中存在数据chunk的冗余复制。

单选题

相比于集中式数据库，分布式数据库具有（　　）的优点。

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