course4資訊系統(tǒng)在實(shí)務(wù)上的應(yīng)用-wenkub
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【正文】 ation for the users ? The data warehousing system also includes a management and control ponents 26 27 How Data Is Stored in the Warehouse Data Repository ? The warehouse data repository stores two types of data in separate tables, which are bined to produce an information package ? Identifying and descriptive data are stored in dimension tables (Figure ) ? Fact tables contain the quantitative measures of an entity, object, or activity (Fig. ) ? An information package identifies all of the dimensions that will be used in analyzing a particular activity. Figure shows the format and Figure includes some sample data 28 29 30 Figure Information Package Format 31 Figure A Sample Information Package 32 The Star Schema ? The key that identifies the dimension and provides the link to connect the dimension tables to the fact table is called a star schema ? Figure shows how the keys in four dimension tables are related to keys in the information package in the center ? Fig. is an example using the four dimension tables: customer, time, salesperson, and product ? The warehouse data repository contains multiple star schemas – one for each activity type to be analyzed 33 34 35 INFORMATION DELIVERY ? The final element in the data warehousing system is the information delivery system ? Information is obtained from the data repository, transformed into information, and made available to users ? Figure shows how the user can navigate the data repository to produce summary information, detailed information, and detailed data ? Figure shows the results of a drillacross navigation, producing outputs in different hierarchies 36 37 38 線上分析系統(tǒng) (ONLINE ANALYTCAL PROCESSING) ? OLAP is a type of software especially developed for data warehouses ? Using OLAP, users can municate with the data warehouse either through a GUI or Web interface, and quickly produce information in a variety of forms, including gr
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