Building the Data Warehouse

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■    Key structure/key resolution as data passes from the operational environment to the DSS environment


■    Attribution


■    What to do when there are multiple sources to choose from


■    What to do when there are no sources to choose from


■    What transformations-encoding/decoding, conversions, etc.-must be made as data is selected for transport to the DSS environment


■    How time variancy will be created from current value data


■■ Structure-how the DSS structure will be created from the operational structure


■■ Relationships-how operational relationships will appear in the DSS environment


■    The output of this step is the mapping of data from the operational environment to the DSS environment.


PARAMETERS OF SUCCESS: When done properly, the source system that serves the needs of the data warehouse uses data that is timely, complete, accurate, near to the source, easy to access, and that conforms to the structure of data warehouse needs.


DSS8—Specifications


PRECEDING ACTIVITY: Source system analysis; data warehouse design.


FOLLOWING ACTIVITY: Programming.


TIME ESTIMATE: One week per extract/integration program.


NORMALLY EXECUTED ONCE OR MULTIPLE TIMES: Once for each program that needs to be written.


Once the interface between the operational and the DSS environments has been outlined, the next step is to formalize it in terms of program specifications. Some of the major issues here include the following:


■    How do I know what operational data to scan?


■    Is the operational data time stamped?

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