course4資訊系統(tǒng)在實(shí)務(wù)上的應(yīng)用(參考版)
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【正文】 s daily operations 25 The Data Warehousing System ? A data warehousing system (Figure ) enters data into the warehouse, transforms the data into information, and makes the information available to users ? Data is gathered from data sources and goes through a staging area before being entered in the warehouse data repository ? An information delivery system obtains data from the warehouse data repository and transforms it into information 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
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