What is the Physical Layer?
The semantic model's physical layer contains objects representing physical data constructs from the back-end data sources that provide data for visualizations and reports.
The physical layer defines the objects and relationships available to the Oracle Analytics query engine for writing physical queries. This layer encapsulates data source dependencies to enable portability and federation.
Typically, each of the semantic model's data sources has its own discrete physical model in the physical layer. The top-level object in the physical layer is a database, and the type of database determines which features and rules apply to that physical model.
Physical tables, joins, and other objects in the physical layer are typically created automatically when you import metadata from the data sources. After these objects have been imported, you can perform tasks such as create additional join paths that aren't in the data source or create alias tables for physical tables that need to serve in different roles.