In part1, the John A. Zachman's Framework was introduced to examine the Enterprise-level business requirements. Oracle Corp. is following this approach for building Fusion.
Most people and organization believe that thier business is too unique and specific for a pre-build solution. Nevertheless the following concept which is essential in building the enterprise architecture is fundamental in achieving the single view of the truth from it. It is the basis for which Oracle is integrating the best breed of applications (Siebel, E-Business, PeopleSoft, etc) using its fusion technology.
A semantic data model (SDM) captures the business view of information for a specific knowledge worker community or analytic application.
A logical data model (LDM) captures the business relationships in the enterprise information independent of a specific analytic application or departmental view.
A physical data model (PDM) captures the implementation design of tables in the data
There can be many semantic data models for the various knowledge worker communities in the enterprise, but there is only one logical data model and only one physical data model in an enterprise data warehouse implementation.
Semantic data models are often implemented using dimensional modeling techniques. Dimensional modeling is a more restrictive form of entity-relationship modeling wherein many-to-many relationships are not allowed in the end user’s view of information. All relationships are mandatory many-to-one and only a single path is allowed between any two levels in a dimensional hierarchy.
These modeling rules ensure enforcement of the MECE principle. MECE means that all metrics are presented as mutually exclusive and collectively exhaustive in the analytic framework. No dollar will be lost and no dollar will be double-counted.
Oracle BI EE follows the same principles reason why it has three layers the Physical, the Logical and the Presentation.