1. MIS 451 Building Business Intelligence Systems Logical Design (3) – Design Multiple-fact Dimensional Model

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3. 3 Design Steps Step 1: Decide facts and fact measurements:  What do customers want to analyze? --- Facts  Find measurements of fact in the source database – Fact Measurements

4. 4 Design Steps Step 2: Decide grain of facts:  Grain is the level of detail at which fact measurements will be stored in data warehouse.  Data warehouse usually stores facts at their lowest level of detail.

5. 5 Design Steps Step 3: Decide fact tables:  Facts  Fact Tables  Fact Measurements  Fact Table Attributes

6. 6 Design Steps Step 4: Determine Primary Keys of Fact Tables Find the natural keys that can uniquely identify records in fact tables from the source database – primary key of fact table Transform natural keys into warehouse keys

7. 7 Design Steps Step 5: Decide key dimension tables for a fact table:  Key dimension tables provide primary key for a fact table. Step 6: Decide analysis dimension tables for a fact table:  Analysis dimension tables provide foreign keys for fact tables. Step 7: Connect separate dimension models using conformed dimension tables  A conformed dimension table is a dimension table shared by fact tables. It can be used to link separate dimensional models into a coherent one.