8 DB2 for z/OS and WebSphere: The Perfect Couple
Figure 1-1 Basic data flow in a DB2 subsystem from z/OS and distributed environments
A request from a distributed environment is very similar to the data flow originating from within
a z/OS environment (local attachment). The significant difference is using the DDF address
space to establish a connection as opposed to an attachment facility.
This is also the case when using JDBC Type 4 connectivity provided by the IBM DB2
Universal JDBC Driver to connect to a DB2 for z/OS subsystem. In this scenario, the
Universal Driver is acting as a DRDA® application requester to establish a connection into
the DDF address space (acting as a DRDA application server) of the DB2 for z/OS
subsystem. This is discussed in more detail in “Accessing DB2 from a Java environment” on
page 19.
1.4 DB2 data structures
DB2 data structures can be conceptualized as a hierarchy of objects that have at least one
relationship to another object. Figure 1-2 on page 9 illustrates a basic relationship between
the DB2 data structures.
TSO
attachment facility
IMS
attachment facility
CICS
attachment facility
CAF
RRSAF
z/OS
environment
Distributed
environment
DDF
address space
MSTR
address space
DBM1
address space
IRLM
address space
DB2 OS/390 or z/OS subsystem

Get DB2 for z/OS and WebSphere: The Perfect Couple now with O’Reilly online learning.

O’Reilly members experience live online training, plus books, videos, and digital content from 200+ publishers.