OBIEE - Common Enterprise Information Model (CEIM) - The Logical Business Model (the three-layer metadata model)
The Logical Business Model is the three-layer metadata model of the repository and its aim is to build a Centralized and consistent conceptual data model known also as a model-centric view (as compared to report-centric view of information).
Each layer appears in a separate pane in the Administration Tool user interface and has a tree structure (similar to the Windows Explorer).
It's also known as:
- internal layers
- three-layer metadata model
- Common Enterprise Information Model (CEIM)
A successful model allows the query process to become a natural process by enabling analysts to structure queries in the same intuitive fashion as they would ask business questions.
Oracle BI Server defines and stores in a central repository three layer where are defined:
- the physical data model in the physical layer
- the logical data model in the business model and mapping
- the conceptual model in the presentation layer
The physical data model layer describes the physical data implementation where the data sources, the tables and columns, the relationships, connections parameters and so on are defined.
The logical data model layer is first abstraction layer and its aim is to design logically a dimensional data (business model) model with fact, dimension, hierarchy and calculations from the physical layer elements (the mapping part of the name).
The presentation layer is the third and last abstraction layer and is in charge of the presentation of the table and columns of the logical data model to the user and client application (with business name, translation management, …)
This bridge data model implementation provides then a conceptual data model which is centralized and consistent.
If the definition of the dimensional of physical data model must change such as:
- a calculation,
- or a source table
it needs only to be changed within the central repository and all analyses/rapport automatically use the new definition.