Chapter 5. SAP usage of LOBs 129
Figure 5-1 Overview of SAP Web AS 6.40 on DB2 for z/OS (c) SAP AG; 2006
The SAP Web AS consists of two stacks, the ABAP stack and the Java stack. The ABAP
stack is based on a kernel written in C or C++. This kernel interacts with the database by
means of a database interface library, which is referred to as lib_dbsl. The Java stack uses
a JDBC driver as connectivity.
SAP has used different connectivity middleware in the past. In this section, we give a short
overview and explain why we only discuss distributed connections in this chapter. With SAP
NetWeaver 2004s, the Integrated Call Level Interface (ICLI) connectivity was phased out and
DB2 Connect was introduced. ICLI is a protocol that was delivered with z/OS; it was used by
SAP in prior releases and essentially provided a subset of DRDA-like connectivity. SAP
NetWeaver 2004s is also the last release to support the application server running natively on
z/OS. Starting with release SAP NetWeaver 2004s, connectivity is only supported using
Distributed Data Facility (DDF) on the server side and DB2 Connect on the client side. This
client-side software can be either the CLI interface of DB2 Connect or the DB2 JDBC
Universal Driver (JCC) for the Java stack. Therefore, we only discuss distributed connections
in this chapter.
5.1.4 Why use LOBs
SAP introduced LOBs to simplify data management. If the burden to handle the length of an
object is shifted to the database, the interfaces to the database become easier to code and to
maintain, thus, reducing the number of problems and therefore the maintenance effort
required at the customer side.
(c) SAP AG; 2006