Download Oracle Database Gateway for DB2 Installation and User's Guide

If you create synonyms or views in the Oracle Database, then you can refer to tables on
the DB2/400 server by using simple names as though the tables were local to the
Oracle Database 10g server.
When the Oracle Database 10g server encounters a reference to a table on the DB2/400
server, the applicable portion of the SQL statement is sent to the gateway for
processing. Any host variables that are associated with the SQL statement are bound
to the gateway and, therefore, to the DB2/400 server.
The gateway is responsible for sending these SQL statements to the DB2/400 server.
The DB2/400 server is responsible for executing the SQL statements and for detecting
errors and returning responses.
1.8.1 Gateway Changes to the AS/400 System
Installing the gateway on the AS/400 system produces the following changes to the
system:
1.
A library is created, with the instance name as given in the first installation panel.
(For an example, refer to Example 4–1, "Install Oracle Database Gateway Panel" on
page 4-4). Almost all of the objects needed for this gateway instance will be found
in this library, with the exception of some objects dealing with service programs
and the items mentioned in parts 3 and 4 of this list.
The gateway can also be installed into a previously created DB2/400 SQL
COLLECTION that contains objects of type *FILE (physical and logical files), a
journal of type *JRN, a journal receiver of type *JRNRCV, and a data dictionary
object of type *DTADCT. The collection name will be the name of the library in
which these objects are created by DB2/400.
2.
A user profile is created. The user profile has the same name as the library that is
created when you install the gateway.
3.
A subdirectory entry is created in the /home directory in the Integrated File
System. The subdirectory entry name will be the same as the instance name. So, if
ORACLE is the instance name, then a subdirectory node will be created at
/home/ORACLE. Further nodes will be created below this node. Agent trace files
will appear (if requested) in a subdirectory of the created node. An initialization
file will also appear in a subdirectory of this node.
4.
A library named ORASRVLIB is created. If the installation software finds that it
must install the service programs that are found on the installation medium, then
a library with a name such as ORASRVnnnn (where nnnn is a number) will be
created. The relevant service programs and a file that is used for Globalization
Support transactions will be placed in that library. Additional files or members
within files may be added to the ORASRVLIB library.
5.
A message queue with the name of the installation library is created in the
QUSRSYS library. This is as a result of using the CRTUSRPRF command to create
the user profile that corresponds to the installation library.
6.
A library named ORATEMP will be created to hold intermediate installation objects
during the install.
1.8.2 SQL Differences
Not all SQL implementations are the same. The Oracle Database 10g server may
support a larger set of built-in functions than the databases that are currently being
accessed through the gateway. Or, the semantics of some functions in the DB2/400
server may not agree with an identically named function in the Oracle Database 10g
1-8 Oracle Database Gateway for DB2/400 Installation and User’s Guide