In Chapter 1, we learned that ETTL is a challenging task. BW uses InfoSources and transfer rules to define the mapping and transformation rules that govern the ETTL process.
In this section, we use IO_MAT as an example to show how to define an InfoSource and transfer rules for characteristic data. In Section 3.6, we will discuss how to define an InfoSource and transfer rules for transaction data.
Step 1. Right-click the newly created Application Component demo, and then select Create InfoSource….
Step 2. Select the option Master data/texts/hierarchies, and then click to continue.
In BW, characteristic data can consist of master data, texts, and hierarchies. Selecting this option ensures that the InfoSource to be created will apply to a characteristic. Section 7.1, "BW Star Schema," discusses master data, texts, and hierarchies and explains their relationships to characteristics.
Step 3. Enter IO_MAT, and then click to continue.
Step 4. Click ) to pass the message.
Step 5. Now we need to tell the newly created InfoSource where to find the data and what the transfer rules are. Right-click Material number, and then select Assign DataSource….
A DataSource is not only a structure in which source system fields are logically grouped together, but also an object that contains ETTL-related information. Four types of DataSources exist:
Chapter 11, Generic R/3 Data Extraction, discusses how to create a DataSource.
Step 6. Enter the source system created in Section 3.1, SS_DEMOFF, in the field Source system, and then click to continue.
DataSources are associated with source systems, so we must first tell BW where to find the DataSources.
Step 7. Click to pass these two messages.
When we created IO_MAT in Section 2.3, we elected to create master data and texts as shown in Screen 2.16. When the source system is a file system, as in this example, because of this selection, BW creates two DataSources: IO_MAT_ATTR for master data, and IO_MAT_TEXT for texts. In the next section, when we load the data, we will see the difference between these two DataSources.
Step 8. Click to activate the transfer rules.
The icon in the Tp column indicates that the transfer rule is a simple one-to-one mapping. By default, BW defines simple one-to-one transfer rules. In this case, we accept the default definition. We will show how to use ABAP to define transfer rules in Section 3.7, "Creating an InfoSource for Transaction Data."
We have created an InfoSource and transfer rules. A status message Transfer rules IO_MAT_ATTR_AH activated will appear at the bottom of Screen 3.15.
Now that the InfoSource and transfer rules are in place, we can create InfoPackages to load the characteristic data.
Part I. Guided Tours
Business Scenario and SAP BW
Creating an InfoCube
Loading Data into the InfoCube
Checking Data Quality
Creating Queries and Workbooks
Managing User Authorization
Part II. Advanced Topics
Aggregates and Multi-Cubes
Operational Data Store (ODS)
Generic R/3 Data Extraction
Appendix A. BW Implementation Methodology
Appendix B. SAP Basis Overview
Appendix C. Glossary
Appendix D. Bibliography