Building the Data Warehouse

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The “best” source of existing data or data found in the Web-based ebusiness environment is determined by the following criteria:


■■ What data in the existing systems or Web-based ebusiness environment is the most complete?


■■ What data in the existing systems or Web-based ebusiness environment is the most timely?


■■ What data in the existing systems or Web-based ebusiness environment is the most accurate?


■    What data in the existing systems or Web-based ebusiness environment is the closest to the source of entry into the existing systems or Web-based ebusiness environment?


■    What data in the existing systems or Web-based ebusiness environment conforms the most closely to the structure of the data model? In terms of keys? In terms of attributes? In terms of groupings of data attributes?


Using the data model and the criteria described here, the analyst defines the system of record. The system of record then becomes the definition of the source data for the data warehouse environment. Once this is defined, the designer then asks what are the technological challenges in bringing the system-of-record data into the data warehouse. A short list of the technological challenges includes the following:


■    A change in DBMS. The system of record is in one DBMS, and the data warehouse is in another DBMS.


■■ A change in operating systems. The system of record is in one operating system, and the data warehouse is in another operating system,


■■ The need to merge data from different DBMSs and operating systems. The system of record spans more than one DBMS and/or operating system. System-of-record data must be pulled from multiple DBMSs and multiple operating systems and must be merged in a meaningful way.

Скачать в pdf «Building the Data Warehouse»