Best Practices for SAP BI using DB2 9 for z/OS - IBM Redbooks

The DSO objects can store the data at the same level of granularity as offered
from the PSA (that is, the source system) because aggregation can be
performed later during reporting.
The example shows how the DSO can be used to integrate data that describes
the same processes but that potentially comes from different source systems
(DataSources). The data can be loaded into SAP BI and stored in different PSA
tables, each having their own transfer structure. Integration is achieved by
applying transfer structure specific rules (that is, transfer rules) while transferring
the data into the same consolidated structure (communication structure of an
InfoSource) of an DSO object.
Thus the DSO objects of the inner level of the operational data store (level 2 in
Figure 12-10 on page 274) offer data that is subject-oriented, consolidated, and
integrated, with respect to the same process that is operated on different source
systems.
The first-level DSO objects are part of the foundation of the data warehouse
because it represents the transactional data archive. This data can be accessed
to create new reporting scenarios based on integrated and consolidated data
from the past.
On the database level, every DSO object consists of three transparent tables:
► Active table
The data in this table is used for reporting.
► Activation queue
This table contains data that is new or modified since the last activation.
► Change log table
The change log is used for the delta update from the DSO object into other
DSO objects or InfoCubes.
Chapter 12. Concepts, activities, and terminology 275