A Siebel business component is a logical entity that combines columns from Siebel tables into a single structure. Business components in the Business Objects Layer correspond to the tables on the Data Objects Layer. When you import Siebel objects as PowerCenter objects, PowerCenter retrieves information from multiple layers and objects.
For example, when you import a Siebel business component as a source definition, the Designer imports the metadata from the business components in the Business Objects Layer and the associated Siebel tables in the Data Objects Layer. When you run a session, the PowerCenter Integration Service extracts the application data from the physical database tables in the underlying database.