SAP BW EXTRACTION

n    Extraction programs that read data from extract structures and send it, in the required format, to the Business Information Warehouse also belong to the data staging mechanisms in the SAP R/3 system as well as the SAP Strategic Initiative products such as APO , CRM and SEM.

n    The IDOC structures or TRFC data record structures (if you choose to use the PSA - Persistent Staging Area) that are generated from the transfer structures for the Business Information Warehouse on the source system side are used for this.

n    These extraction tools are implemented on the source system side during implementation and support various releases.

n    In non-SAP applications, similar extraction programs can be implemented with the help of third party providers. These then collect the requested data and send it in the required transfer format using BAPIs to the SAP Business Information Warehouse.

n    The OLTP extraction tables form the basis of a DataSource on an R/3 OLTP system. The structure is written in the OLTP using the data elements that describe the available data, usually from a table view.

n    For an R/3 OLTP source system, the ‘DataSource Replication’ step is provided to duplicate the DataSource is replicated with its relevant properties in BW. Once there you can assign it to an InfoSource.

n    You can request the Metadata for a DataSource, the Metadata for an application component, or all the Metadata of a source system:

Ÿ    To replicate the Metadata of a DataSource, choose Source System Tree ® Your Source System à DataSource Overviewà Your Application Components à Your DataSource à Context Menu (right mouse click) à Replicate DataSources in the BW Administrator Workbench

Ÿ    To replicate the Metadata from a source system into BW for an application component, choose Source System Tree ® Your Source System ® DataSource Overview ® Your Application Components ® Context Menu (right mouse click) à Replicate DataSources in the BW Administrator Workbench

Ÿ    To update all the Metadata of a source system, choose Source System Tree à Your Source System à Context Menu (right mouse click) à Replicate DataSources in the BW Administrator Workbench

n    All application data must be described in SAP BW using meta data.  The InfoObjects used for this are not just transaction and master data but also relationship sets such as attributes or hierarchies for master data.

n    Further detailed information, such as exchange rates, comes from the operative applications.

n    For reasons of performance, delta update mechanisms are also supported in most application areas on the OLTP side.  With a periodic data transfer into BW, only those data records and objects that have changed or been added since the last data transfer need to be considered.

The mechanisms used are explained in detail later

n    The transfer structures are oriented to the data formats of the source system.

n    The transfer rules are processed with the transfer of the data from the source system oriented transfer structure to the BW oriented communication structure and, for the most part, have the objective of the homogenization of data from different source systems.

If data is being loaded from flat files,it must be able to be described with SAP BW InfoObjects. You can also create new InfoObjects for this purpose easily in the SAP BW

  

n    Updating is controlled separately for each key figure.  The characteristic values for updating can be established separately for each key figure.

n    Different updating methods can be chosen interactively, and you can also formulate as many algorithms in ABAP as you like via the function extensions.  Requirement handling is also supported.

n    You proceed in a similar way with the transfer of data from non-SAP systems into the Business Information Warehouse: You define transfer and communication structures and then create transfer and update rules for them that fine tune the data flow. You describe the structures using InfoObjects that can be created individually where necessary.

n    Using third party tools you can implement the necessary infrastructure for data staging for the SAP Business Information Warehouse in the non-SAP systems.  Therefore, InfoSources, InfoObjects, extract structures and extract programs are available that communicate with the Business Information Warehouse using BAPIs.

n    Meta data such as InfoObjects and InfoSources can then also be loaded from the external (non-SAP)  OLTP into the Business Information Warehouse.

In the simplest case you use the Business Information Warehouse file interface in order to import MS-Excel files in CSV format, for example.  You store the record description for the data file in the Business Information Warehouse as a transfer structure

n    The SAP BW extractors carry out a number of functions in the SAP OLTP, in order to guarantee smooth communication between SAP OLTP and SAP BW.

n    These tasks must be carried out by external software in non-SAP Systems, that are set up in the BAPI interfaces of the SAP BW.

Various businesses have already been certified as official third party providers in this field. A complete list can be found on the SAPnet BW homepage.

Virtually any source of data can be extracted for use in the Business Information Warehouse

n    Two options for data transfer are possible

Ÿ    TRFC (chosen by selecting PSA in the transfer structure)
TRFCs are faster than ALE but there is a 255 field and a 1962 byte limit imposed.  The transfer is asynchronous and runs in the background.

Ÿ    ALE (IDOC)
Here there is a 1000 byte limit imposed.  The load process takes place in two steps and tracing of the status of each step is provided.

n    Benefits of TRFC

Ÿ    Improved performance when loading data.

Ÿ    Overcoming the 1000 byte limit (now a maximum of 255 fields and 1962 bytes).

Ÿ    Possibility to synchronize InfoSources.

API to access the data stored in the ODS (read and update).