Transfer & Update rules

A DataSource describes in the form of field structures the data that isavailable in a source system. The DataSource consists of the extract structure(all prepared fields) and the transfer structure (a selection of fields from theextract structure). The DataSource is replicated in SAP BW.

AnInfoSource is a collection of information that logically belongs together,gathered into a single unit. The communication structure is the field structurein which the information is stored.

Transfer rules transform data from several transfer structures into a singlecommunication structure.Transfer rules are defined in BI for harmonizing or cleaning up data fromthe transfer structure to the communication structure, transfer rules are DataSource-specific, and consequently source system-specific. It has two transfer method: PSA and IDoc, only can connect Datasource.

Update rules transform data from a communication structure into one or moredata targets. cannot load hierarchies.