LOGICAL MODELING
When reviewing these problems with the objective of trying to formulate potential solutions, the following are the main requirements that need to be satisfied:
Accurate reporting of the facts. It is very important that, in a dimensional model, whenever a fact entry is joined to a dimension entry, the fact must join to the correct dimension with respect to time. Where a snowflake schema exists, the fact entry must join to the correct dimension entry no matter where that dimensional entry appears in the hierarchy. In reality, it is recognized that this can never be wholly achieved in all cases, as deficiencies in the capture of data from the operational systems of the organization will impinge on our ability to satisfy this requirement. ...
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