The Presentation layer provides a way to present customized, secure, role-based views of a business model to users. Role-based views provide object security and also provide a way to hide some of the complexity of the business model.
The Presentation layer also provides some of the functionality of the metadata model, such as the ability to set an implicit fact column.
Presentation layer views are called subject areas (formerly called presentation catalogs). You can have a subject area that is identical to your business model, or you can provide smaller, role-based subject areas that show a single subject, or that support a particular business role. Create subject areas that help you organize your content in a way that makes sense for your users.
Subject areas in the Presentation layer appear as catalogs to client tools that use the Oracle BI Server as an ODBC data source. Subject areas contain presentation tables, columns, hierarchies, and levels.
Even though the Logical SQL requests from Answers and other clients query the presentation tables and columns, the real logic for entities, relationships, joins, and so on is in the Business Model and Mapping layer. The primary function of the Presentation layer is to provide custom names, dictionary entries, organization, and security for different groups of users.