计算机世界网-周报全文－数据仓库环境(4) 中英文对照计算机专业时文选读(541)

数据仓库环境(4) 中英文对照计算机专业时文选读(541)
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Data Warehouse Environment(4)
·Generalized copy utilities bulk-copy data from a source system to a target system. The focus of these products tends to be on thehigh-speed transfer of data, rather than on data integration, cleanup and transformation.
·Database gateways, as a rule, focus on providing workstation end users with access to operational(or data warehouse) databases. This approach is often used as an alternative to building separate data warehouse systems, since it gives the user direct access to operational data.
There are many approaches to acquiring data and copying it into a data warehouse system.
The direction of the industry is to use a mix of code generators and data replication tools.
MANAGEMENT COMPONENT
The management component consists of a set of services for use by other warehouse components, and for managing warehouse data collections. A data collection is a set of data  of interest to a specific user or group of users. Data collections are derived from the base data created by the data acquisition component. The services provided by the management component include a data maintenance service for deriving new data collections from warehouse base data and a distribution service for exporting warehouse data to decentralized warehouse database servers and her end-user decision support systems. The management component also provides services for handling the security, archiving, backup and recovery, and monitoring of base data and data collections. Often these services employ the facilites provided by underlying operating system and database software.
INFORMATION DIRECTORY COMPONENT
The information directory component of data warehouse contains information(known as meta data)about the data the warehouse databases. A key benefit of the information directory is that it helps business users understand what information exists in the warehouse and how to access and use it.
The three main elements of the information directorye thetechnical directory, the business directory and the information navigator.
The technical directory contains information about warehouse data for use warehouse designers and administrators. It has information about data sources, targets, cleanup rules, transformation rules and mapping between data sources and the warehouse databases. Most of the information in the technical directory is created when the warehouse designer defines the data sources and targets, as well as the rules to be applied when copying data intoe warehouse. It also be mported from an external system, such as a 3GLpybook library, DBMS system catalog or CASE tool.
Information about the amount of data in the warehouse and the date it was created or updated should also be stored in the directory. Ideally, this information should be collected by the toolsployed acquire data from the source systems and delivered the warehouse database.
formation about how end users access and use warehouse data shouldso be trapped and added to the technical directory to enable designers and administrators to tune and enhance the data warehouse.
【参考译文】
数据仓库环境(4)
·归一化复制实用程序大批量地把数据从源系统复制到目的系统。这些产品的着眼点是进行高
速的数据传输,而不是数据的集成、清理和变换。
·数据库入口原则上向工作站最终用户提供对日常运作(或数据仓库)数据库的访
问。此方法常常用作构筑独立数据仓库系统的一种替代办法,因为它让用户直接访问日常运
作的数据。
采集数据并把它复制到数据仓库系统有很多种方法。工业界的走向是混合使用编
码生成器和数据复制工具。
管理部件
管理部件由一组供其它仓库部件使用和管理仓库数据集合的服务组成。数据集合
是一组对特定用户或用户群感兴趣的数据。数据集合是从数据采集部件生成的基础数据中
得到的。管理部件提供的服务包括对从仓库的基本数据推导出来的新数据集合的数据维护
服务、把仓库数据外送至分散的仓库数据库服务器和其它最终用户决策支持系统的分配服
务。管理部件还提供对库数据和数据集合的安全、归档、备份和恢复以及监测等项的处理
服务。这些服务常常要用到基本操作系统和数据库软件提供的一些功能。
信息目录部件
数据仓库的信息目录部件包含了关于仓库数据库中数据的信息(称作元数据)。信
息目录的主要长处是有助于业务用户了解仓库存放了哪些信息以及如何访问和使用它们。
信息目录的三大部分是技术目录、业务目录以及信息引导器。
技术目录包含了有关供仓库设计人员和管理人员使用仓库数据信息的。它拥有关
于数据源、目标、清理规则、变换规则以及数据源和仓库数据库之间映像的信息。技术目
录中的多数信息是在仓库设计人员定义数据源和目标时以及定义在把数据复制到仓库中运
用的规则时生成的。它也可以由外部系统送入,如第三代语言的复制书库、DBMS系统目录表
或CASE工具。
有关仓库中的数据量和生成或更新的日期的信息也应存储在目录中。理想的情况
是,这种信息应该由使用的工具收集,以便从源系统采集数据并把它送到仓库数据库。关于
最终用户如何访问和使用仓库数据的信息也应该进行捕捉,并加到技术目录上,以使设计人
员和管理人员调整和增强数据仓库。
（计算机世界报 1995年 第19期）