The Business Model and Mapping layer (known also as Business Model):

• is the layer in the middle of the logical business model.
• permit to model logical dimensional models which are a reorganization of the physical data model into a logical data dimensional model.

During the design process of your logical model, you have to define:

• the fact table with measures
• the dimension table
• the hierarchy (of Dimension in OBI term)

Because they mirror the way people think about business information, dimensional model (star or snowflake model) can be understood by non-technical business analysts.
The SQL required to query a Siebel Analytics Server business model is even less complex than the SQL required to query an RDBMS dimensional model. Join information, aggregation functions, and Group By clauses are not needed when querying through the Analytics server.
Its server-side capabilities, together with its data modeling capabilities, provide that bridge, which allows simple SQL to pose complex business questions, regardless of where the data is physically located and independent of the physical model in which the data is stored.