BW 200 BW Overview Completed

BAPI and ALE technology takes care of communication between these various systems.

Individual dimension values can be subdivided further into master data tables. In this way, master data tables, text tables, hierarchy data tables, and dimension tables, are grouped in a starlike formation around one central fact table. This structure is called an extended star schema. In an analysis, the data from the smaller tables at the edge of the star schema, is collected together first, before the corresponding data in the fact table is accessed using the keys.

The fact table and the relevant dimension tables of an InfoCube are connected with one another by the dimension keys. A dimension key is provided by the system, one per characteristic combination in a dimension table.

InfoObject is the generic term for all business objects, such as customer, product, region, sales,

head count and so on. As part of the BW Metadata Repository, InfoObjects include a technical definition as well as business logic. InfoObjects are used across the whole BW system (an InfoSource is a collection of InfoObjects). InfoObjects are either key figures or characteristics. Special characteristics are time and unit. The InfoObject definition includes: General information (data dictionary, Business Explorer, management, transfer routines) Master data/attributes Hierarchies Texts Compound information SAP InfoObjects start with the 0. Customer-defined InfoObjects start with a letter from A to Z.

Data extraction takes place in two components: the DataSource and the InfoSource. DataSources include extraction source structures and transfer structures. Data is staged in the extraction source structure and the transfer structure, and transferred into the BW system by ALE or tRFC. An InfoSource is a set of information that logically belongs together. InfoSources manage transaction data and master data (attributes, texts, and hierarchies). InfoSources describe all the information that is available for a business transaction or a type of business transaction (for example, cost center accounting). Transfer structures support the transfer of data in a DataSource between a source system and the SAP BW system to which the source system is connected. The transfer structure transports the DataSource data from a source system to a SAP BW system. Transfer rules pass the data on to the InfoSource. The communication structure is independent of the source system and is generated from the InfoSource. It is filled from the transfer structure, according to the transfer rules. The communication structure contains all the fields in an InfoSource. This method of extracting and transferring cleansed data in the communication structure is called data staging. Every InfoCube has update rules that determine how data from the communication structure is stored in the InfoCube.

Transfer

rules connect a DataSource to an InfoSource. The logic behind the assignment of DataSource-type data elements to InfoObjects in the InfoSource is contained in the transfer rules. Update rules determine in what form the data from the communication structure is updated in the InfoCube. Data can be manipulated by either set of rules. If you want to have a consistent definition of data for all InfoCubes, the best way of converting the data into a consistent format is by using the transfer rules. Update rules can be used for InfoCube-specific data conversions.

There are two ways of extracting data: You can use IDocs to load the data into a data target (InfoCube) directly. If you choose this method, all of the data is transferred by way of the IDocs. Alternatively, you can load the data into the PSA. With this method, Info-IDocs are sent at the start and end of the extraction process, but the data itself is not sent by IDocs.