Transcript InfoCube

How to Model a Data Warehouse?
Reporting team May 16, 2004
Wayne Lee
Data Warehouse Architecture
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Data is represented by a Star (InfoCube)
Organized to provide good performance
Flexible to organizational change
Information is provided on aggregated level
Generally NO transaction reporting
BW Star Schema
Master Data
(Attributes describing
a characteristic)
Dimension
Characteristics
(By What are
Key Figures viewed)
Dimension
Characteristics
(By What are
Key Figures viewed)
Master Data
(Attributes describing
a characteristic)
Key Figures
(Everything what
can be counted)
Master Data
(Attributes describing
a characteristic)
Dimension
Characteristics
(By What are
Key Figures viewed)
Dimension
Characteristics
(By What are
Key Figures viewed)
InfoCube
Master Data
(Attributes describing
a characteristic)
How To Decide Where To Place
Data Elements ?
• Fact Table (Key Figures)
– All objects to be counted
– All values to be calculated
• Dimensions (Characteristics)
– All organizational objects required to preserve the
historical truth
– All objects by which Key Figures are to be viewed
(Slice & Dice)
• Master Data (Attributes)
– All object describing a characteristics
– Generally only for display (informational)
– Exceptional Drill-Down (Navigational Attributes)
Additional Considerations
• Historical Truth vs. Flexibility to Change
– Yesterday or Today
• A past result can be reproduced
– Yesterday is Today
• A past result is viewed with current organization
(characteristics)
– Today is Yesterday
• Today’s results is viewed with past organization
(characteristics)
– A combination of the above
• Object must reside in both Dimension and Master Data
Performance
Master Data
(Attributes describing
a characteristic)
Dimension
Characteristics
(By What are
Key Figures viewed)
Dimension
Characteristics
(By What are
Key Figures viewed)
Master Data
(Attributes describing
a characteristic)
Key Figures
(Everything what
can be counted)
Master Data
(Attributes describing
a characteristic)
Dimension
Characteristics
(By What are
Key Figures viewed)
Dimension
Characteristics
(By What are
Key Figures viewed)
Master Data
(Attributes describing
a characteristic)
InfoCube
Good Performance
Less Performance