Modeling data in the BW principally involves data staging and modeling the layers of a Data Warehouse.
The concept of layered scalable archictecture (LSA) assists you in designing and implementing various layers in the BW system for data acquisition, Corporate Memory, data distribution and data analysis. Here we differentiate between two main layers: the Enterprise Data Warehouse layer and the Architected Data Mart layer.
The following graphic illustrates the structure of the different layers:
The tool you use for modeling is the Data Warehousing Workbench. The graphical user interface makes it easier for you to create data flows. You can model top-down data flows using this interface. SAP provides you with predefined data flow templates. These are best practice models that help you to create optimized models.
More information: Graphical Modeling
You can also create bottom-up objects by using the object trees in the Data Warehousing Workbench. Objects created in this way can then be used in the graphical data flow modeling. For more information on creating individual objects, read the relevant object documentation.