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

Metadata plays a fundamental role in turning data into information. To clarify,
information is typically defined as data-in-context. In that process, the metadata
provides the context and an understanding of how various data elements are
linked. Business rules are applied to the combination of data and metadata to
create useful business information. The information model of SAP BI provides
consistent and integrated metadata for all objects across the data warehousing
process.
Figure 12-1 shows the elements of the SAP BI information model, all of which
store metadata. In addition, the PSA, DSO, and InfoCube also store transactional
or master data.
Master data is data that remains unchanged over long periods of time. Examples
of master data are customer name and address, or an organizational structure.
See Figure 12-1.
Data
Source
PSA
Mapping and
Transfer
Rules
Info
Source
Figure 12-1 Elements of the information model
12.2.1 Other key elements in the information model
In addition to InfoObjects, here is a list of other key elements in the information
model:
► DataSource
Data is transferred into SAP BI in a flat structure; that is, it is a table rather
than a multidimensional data structure. DataSources contain the definitions of
the source data.
► Persistent Staging Area (PSA)
In the SAP BI information model, data is physically stored in PSA objects.
These are collections of flat tables holding extracted data that has not yet
been cleaned or transformed. The PSA is the initial storage area of data
258 Best Practices for SAP BI using DB2 9 for z/OS
Update
Rules
ODS
Object
ODS
Object
Update
Rules
Info
Cube
Info
Cube