Data Flow

A common BW scenario is moving data from the R3 or Transaction system to the Data Warehouse.

Let us now look at the data flow in the BW system.

The data can be brought in to the BW system from various sources, as shown below.



The DataSource is the replicated meta data structure from the source system (Eg: SAP R/3) and the mapping between the DataSource in external system and BW is 1:1.

The structure of this DataSource is known as Transfer Structure.

Creating InfoSource:

Choose the InfoSource tree of the Data Warehousing Workbench to create InfoSources for an SAP source system. From the context menu of the affected application component, choose Additional Functions -> Create InfoSource 3.x

1. Select the type.

2. Under InfoSource, enter the technical name of the InfoSource, and then a description.

3. Assign a source system to the InfoSource and confirm.

4. From the proposal list, select the DataSource from which transaction data is to be loaded.

Transfer structure maintenance automatically appears.

The system automatically offers you suitable transfer rules, but you can modify these.

5. Maintain the transfer structure. Assign InfoObjects to the fields of the DataSource.

6. The communications structure is adjusted automatically, but you can also include more fields. Activate your selection.

7. Maintain the transfer rules.

8. Activate the InfoSource.

Communication Structure:
The communication structure is localized in the SAP Business Information Warehouse and displays the structure of the InfoSource. It contains all of the InfoObjects belonging to the InfoSource of the SAP Business Information Warehouse.

Processing Transfer Rules:
When you have maintained the transfer structure and the communication structure, you use the transfer rules to determine how you want the transfer structure fields to be assigned to the communication structure InfoObjects. You can arrange for a 1:1 assignment. You can also fill InfoObjects using routines, formulas, or constants.


You maintain the transfer rules in the InfoSource tree of the Administrator Workbench. choose Your Application Components®Your InfoSource®Context menu (right mouse-click) ®Change.

Select a transfer method (PSA or IDOC). We recommend the PSA transfer method.

The transfer structure is displayed in the right half of the screen along with the selected DataSource fields. The system uses the data elements to help it suggest InfoObjects that could be assigned to the corresponding fields of the DataSource. These suggested InfoObjects are displayed in the left column of the transfer structure.

You do not have to assign InfoObjects to all the DataSources fields at this point. Using the transfer rules, you can also fill the InfoObjects of the communication structure with a constant or from a routine.


In the left half of the screen, the communication structure InfoObjects are displayed as well as the transfer rules that the system proposes.

By selecting one row from both the left-hand side and the right-hand side of the screen, you can use the arrows to assign fields from the transfer structure to the InfoObjects of the communication structure.

For InfoObjects with the conversion routines ALPHA, NUMC or GJAHR, you can set the Optional Conversion key figure.

You can create a start routine if you use the PSA to load the data, to improve system performance. For example, when you check if a certain request is already available in an ODS object, and makes the update rules consistent.


You can enhance or modify the transfer rules suggested by the system.

To do this, select a transfer rule type by clicking on the corresponding Type symbol in the appropriate row:

· InfoObject: The fields are transferred from the transfer structure and are not modified.

· Constants: An InfoObject is filled by a fixed value.

You could, for example, assign the fixed value US to the InfoObject 0COUNTRY.

· Formula: An InfoObject is filled with a value that is determined using a formula.

· Routine: An InfoObject is filled from a local transfer routine.

Local transfer routines are ABAP programs that you can create, modify, or transfer. The routine only affects the selected InfoObject in the relevant communication structure.

8. Activate the transfer rules. Data can be loaded from the source system in an activated version only.

Q. Difference between Update and Transfer rules.

A. Transfer rules are used to move data from DataSource (Transfer Structure) to InfoSource (Communication Structure)

Update Rules are used to move data from InfoSource to InfoProvider.

The update rules and transfer rules allows us to manipulate the data at various stages in the data load process, as per the business reporting requirement. An InfoSource collects data from many DataSources and Transfer rules are used to modify data here. An InfoProvider collects data from more than one InfoSource and update rules are used to modify data here.

Q. How does partitioning an InfoCube helps?

A.It helps by improving the query performance and maintenance of InfoCube .

Note: The content on this blog including some figures, is taken from SAP help.