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Oracle® Database Gateway Installation and Configuration Guide
11g Release 2 (11.2) for Microsoft Windows

Part Number E12061-05
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14 Configuring Oracle Database Gateway for DRDA

After installing the gateway, perform the following tasks to configure Oracle Database Gateway for DRDA:

  1. Configure the Gateway Initialization Parameter File

  2. Configure Oracle Net for the Gateway

  3. Configure Two-Phase Commit

  4. Create Tables and Views for Data Dictionary Support

  5. Configure the Oracle Database for Gateway Access

  6. Create Database Links

  7. Configure the Gateway to Access Multiple DRDA Databases

SQL scripts are provided to perform steps such as creating the HS_TRANSACTION_LOG table, removing obsolete tables and views, and creating tables and views to provide data dictionary support.

These scripts must be run on the DRDA Server platform using a database native tool (such as SPUFI on DB2 UDB for Linux, UNIX, and Windows), because no tool is provided with the gateway to execute these scripts. Note that when running these scripts, the user ID used must be suitably authorized.

SQL scripts are located in the dg4db2/admin directory. Appropriate platform scripts are designated by having the DB2 platform identifiers (eg: "zos", "as400" and "luw") and version specific numbers (eg: vw7, vw8) in their file names.

14.1 Configure the Gateway Initialization Parameter File

Perform the following tasks to configure the gateway initialization parameter file

  1. Choose a System Identifier for the Gateway

  2. Customize the Initialization Parameter File

14.1.1 Choose a System Identifier for the Gateway

The gateway system identifier (SID) is an alphanumeric character string that identifies a gateway instance. You need one gateway instance, and therefore one gateway SID, for each DRDA database you are accessing. However, if you want to access two DRDA databases, you need two gateway SIDs, one for each instance of the gateway. If you have one DRDA database and want to access it sometimes with one set of gateway parameter settings, and other times with different gateway parameter settings, you can do that by having multiple gateway SIDs for the single DRDA database. The SID is used as part of the file name for the initialization parameter file.

14.1.2 Customize the Initialization Parameter File

Tailor the parameter file with additional parameters as needed. Refer to Appendix C, "Initialization Parameters" for a list of supported initialization parameters. Also refer to Chapter 15, "Security Considerations" for security aspects to tailoring the parameter file.

14.2 Configure Oracle Net for the Gateway

The gateway requires Oracle Net to communicate with the Oracle database. After configuring the gateway, perform the following tasks to configure Oracle Net to work with the gateway:

  1. Configure Oracle Net Listener for the Gateway

  2. Stop and Start the Oracle Net Listener for the Gateway

14.2.1 Configure Oracle Net Listener for the Gateway

The Oracle Net Listener listens for incoming requests from the Oracle database. For the Oracle Net Listener to listen for the gateway, information about the gateway must be added to the Oracle Net Listener configuration file, listener.ora. This file by default is located in ORACLE_HOME\network\admin, where ORACLE_HOME is the directory under which the gateway is installed.

The following entries must be added to the listener.ora file:

  • A list of Oracle Net addresses on which the Oracle Net Listener listens

  • The executable name of the gateway that the Oracle Net Listener starts in response to incoming connection requests

A sample of the listener.ora entry (listener.ora.sample) is available in the ORACLE_HOME\dg4db2\admin directory where ORACLE_HOME is the directory under which the gateway is installed.

14.2.1.1 Syntax of listener.ora File Entries

The Oracle database communicates with the gateway using Oracle Net and any supported protocol adapters. The syntax of the address on which the Oracle Net Listener listens using the TCP/IP protocol adapter is as follows:

LISTENER=
        (ADDRESS= 
          (PROTOCOL=TCP)
          (HOST=host_name)
          (PORT=port_number))

Where:

Variable Description
host_name is the name of the machine on which the gateway is installed.
port_number specifies the port number used by the Oracle Net Listener. If you have other listeners running on the same machine, then the value of port_number must be different from the other listeners' port numbers.

To direct the Oracle Net Listener to start the gateway in response to incoming connection requests, add an entry to the listener.ora file.

Note:

You must use the same SID value in the listener.ora file and as the tnsnames.ora file which will be configured in the next step.
SID_LIST_LISTENER=
   (SID_LIST=
      (SID_DESC= 
         (SID_NAME=gateway_sid)
         (ORACLE_HOME=oracle_home_directory)
         (PROGRAM=dg4db2)
      )
   )

Where:

Variable Description
gateway_sid specifies the SID of the gateway and matches the gateway SID specified in the connect descriptor entry in the tnsnames.ora file.
oracle_home_directory specifies the Oracle home directory where the gateway resides.
dg4db2 specifies the executable name of the Oracle Database Gateway for DRDA.

If you are already running a Oracle Net Listener that listens on multiple database SIDs, add only the following syntax to SID_LIST in the existing listener.ora file:

SID_LIST_LISTENER=
(SID_LIST= 
   (SID_DESC=.
     .
   )
   (SID_DESC=.
     .
   )
   (SID_DESC=
      (SID_NAME=gateway_sid)
      (ORACLE_HOME=oracle_home_directory)
      (PROGRAM=dg4db2)
   )
)

See Also:

Oracle Database Net Services Administrator's Guide for information about changing the listener.ora file.

14.2.2 Stop and Start the Oracle Net Listener for the Gateway

You must stop and restart the Oracle Net Listener to initiate the new settings, as follows:

  1. From the Start menu, select Settings, Control Panel and then select Services.

  2. Select the Oracle Net Listener service for the gateway.

  3. If the service is already running, click Stop to stop it.

  4. Click Start to start or restart the service.

14.3 Configure Two-Phase Commit

Support for Two-Phase Commit requires running the ORACLE_HOME\dg4db2\admin\dg4db2_tx.sql script on the DB2 server. This script will create objects used by the gateway for Two-Phase Commit. Edit the script and replace the default recover account schema ("RECOVER") with the account name specified for the HS_FDS_RECOVERY_ACCOUNT initialization parameter. Refer to Appendix C, "Initialization Parameters" for more details.).

14.4 Create Tables and Views for Data Dictionary Support

To enable data dictionary translation support, data dictionary tables and views have to be created on each non-Oracle system that you want to access through the gateway.

Perform the following steps to create the data dictionary tables and views using database native tools:

  1. Upgrade from a previous gateway release

    If you are upgrading from a previous version of the gateway then run the appropriate script to drop the old data dictionary definitions.

    • If connecting to DB2 UDB for Linux, UNIX, and Windows, then run

      ORACLE_HOME\dg4db2\admin\dg4db2_luw_drop.sql
      
    • If connecting to DB2 UDB for z/OS, then run

      ORACLE_HOME\dg4db2\admin\dg4db2_zos_drop.sql
      
    • If connecting to DB2 UDB for iSeries, then run

      ORACLE_HOME\dg4db2\admin\dg4db2_as400_drop.sql
      
  2. Create the data dictionary tables

    Run the appropriate script to create the data dictionary tables.

    • If connecting to DB2 UDB for Linux, UNIX, and Windows, then run

      ORACLE_HOME\dg4db2\admin\dg4db2_luw_tab.sql
      
    • If connecting to DB2 UDB for z/OS, then run

      ORACLE_HOME\dg4db2\admin\dg4db2_zos_tab.sql
      
    • If connecting to DB2 UDB for iSeries, then run

      ORACLE_HOME\dg4db2\admin\dg4db2_as400_tab.sql
      
  3. Create the data dictionary views

    Run the appropriate script to create the data dictionary views:

    • If connecting to DB2 UDB for Linux, UNIX, and Windows, then run

      For DB2 UDB for Linux, UNIX, and Windows V7:

      ORACLE_HOME\dg4db2\admin\dg4db2_luw_vw7.sql
      

      For DB2 UDB for Linux, UNIX, and Windows V8:

      ORACLE_HOME\dg4db2\admin\dg4db2_luw_vw8.sql
      
    • If connecting to DB2 UDB for z/OS then run

      For DB2 UDB for z/OS V7 (RACF security):

      ORACLE_HOME\dg4db2\admin\dg4db2_zos_vw7r.sql
      

      For DB2 UDB for z/OS V7 (DB2 security):

      ORACLE_HOME\dg4db2\admin\dg4db2_zos_vw7s.sql
      

      For DB2 UDB for z/OS V8 (RACF security):

      ORACLE_HOME\dg4db2\admin\dg4db2_zos_vw8r.sql
      

      For DB2 UDB for z/OS V8 (DB2 security):

      ORACLE_HOME\dg4db2\admin\dg4db2_zos_vw8s.sql
      
    • If connecting to DB2 UDB for iSeries, then run

      For DB2 UDB for iSeries V5.1:

      ORACLE_HOME\dg4db2\admin\dg4db2_as400_vw51.sql
      

      For DB2 UDB for iSeries V5.2:

      ORACLE_HOME\dg4db2\admin\dg4db2_as400_vw52.sql
      

      For DB2 UDB for iSeries V5.3:

      ORACLE_HOME\dg4db2\admin\dg4db2_as400_vw53.sql
      

14.5 Configure the Oracle Database for Gateway Access

Before you use the gateway to access DB2 data you must configure the Oracle database to enable communication with the gateway over Oracle Net.

To configure the Oracle database you must add connect descriptors to the tnsnames.ora file. By default, this file is in ORACLE_HOME\network\admin, where ORACLE_HOME is the directory in which the Oracle database is installed. You cannot use the Oracle Net Assistant or the Oracle Net Easy Config tools to configure the tnsnames.ora file. You must edit the file manually.

A sample of the tnsnames.ora entry (tnsnames.ora.sample) is available in the ORACLE_HOME\dg4db2\admin directory where ORACLE_HOME is the directory under which the gateway is installed.

See Also:

Oracle Database Administrator's Guide for information about editing the tnsnames.ora file.

14.5.1 Configuring tnsnames.ora

Edit the tnsnames.ora file to add a connect descriptor for the gateway. The following is a syntax of the Oracle Net entry using the TCP/IP protocol.

connect_descriptor=
   (DESCRIPTION=
      (ADDRESS=
         (PROTOCOL=TCP)
         (HOST=host_name)
         (PORT=port_number)
      )
      (CONNECT_DATA=
         (SID=gateway_sid))
      (HS=OK))

Where:

Table 14-1 Gateway Parameters for tnsnames.ora File

Variable Description

connect_descriptor

is the description of the object to connect to as specified when creating the database link, such as dg4db2.

Check the sqlnet.ora file for the following parameter setting:

names.directory_path = (TNSNAMES)

Note: The sqlnet.ora file is typically stored in ORACLE_HOME\network\admin.

TCP

is the TCP protocol used for TCP/IP connections.

host_name

specifies the machine where the gateway is running.

port_number

matches the port number used by the Oracle Net Listener that is listening for the gateway. The Oracle Net Listener's port number can be found in the listener.ora file used by the Oracle Net Listener. See "Syntax of listener.ora File Entries".

gateway_sid

specifies the SID of the gateway and matches the SID specified in the listener.ora file of the Oracle Net Listener that is listening for the gateway. See "Configure Oracle Net Listener for the Gateway" for more information.

(HS=OK)

specifies that this connect descriptor connects to a non-Oracle system.


14.6 Create Database Links

Any Oracle client connected to the Oracle database can access DB2 data through the gateway. The Oracle client and the Oracle database can reside on different machines. The gateway accepts connections only from the Oracle database.

A connection to the gateway is established through a database link when it is first used in an Oracle session. In this context, a connection refers to the connection between the Oracle database and the gateway. The connection remains established until the Oracle session ends. Another session or user can access the same database link and get a distinct connection to the gateway and DRDA database.

Database links are active for the duration of a gateway session. If you want to close a database link during a session, you can do so with the ALTER SESSION statement.

To access the DRDA server, you must create a database link. A public database link is the most common of database links.

SQL> CREATE PUBLIC DATABASE LINK dblink CONNECT TO
2  "user" IDENTIFIED BY "password" USING 'tns_name_entry';

Where:

Variable Description
dblink is the complete database link name.
tns_name_entry specifies the Oracle Net connect descriptor specified in the tnsnames.ora file that identifies the gateway

After the database link is created you can verify the connection to the DRDA database, as follows:

SQL> SELECT * FROM DUAL@dblink;

See Also:

Oracle Database Administrator's Guide and Oracle Database Heterogeneous Connectivity User's Guide for more information about using database links.

14.7 Configure the Gateway to Access Multiple DRDA Databases

The tasks for configuring the gateway to access multiple DRDA databases are similar to the tasks for configuring the gateway for a single database. The configuration example assumes the following:

14.7.1 Multiple DRDA Databases Example: Configuring the Gateway

Choose One System ID for Each DRDA Database

A separate instance of the gateway is needed for each DRDA database. Each instance needs its own gateway System ID (SID). For this example, the gateway SIDs are chosen for the instances that access the DRDA databases:

  • dg4db22 for the gateway accessing database db2.

  • dg4db23 for the gateway accessing database db3.

Create Two Initialization Parameter Files

Create an initialization parameter file for each instance of the gateway by copying the original initialization parameter file: ORACLE_HOME\dg4db2\admin\initdg4db2.ora, twice, naming one with the gateway SID for db2 and the other with the gateway SID for db3:

> cd ORACLE_HOME\dg4db2\admin
> copy initdg4db2.ora initdg4db22.ora
> copy initdg4db2.ora initdg4db23.ora

Note:

If you have multiple gateway SIDs for the same DRDA database because you want to use different gateway parameter settings at different times, follow the same procedure. You create several initialization parameter files, each with different SIDs and different parameter settings.

14.7.2 Multiple DRDA Databases Example: Configuring Oracle Net Listener

Add Entries to listener.ora

Add two new entries to the Oracle Net Listener configuration file, listener.ora. You must have an entry for each gateway instance, even when multiple gateway instances access the same database.

The following example shows the entry for the original installed gateway first, followed by the new entries:

SID_LIST_LISTENER=
(SID_LIST=
   (SID_DESC=
      (SID_NAME=dg4db2)
      (ORACLE_HOME=oracle_home_directory)
      (PROGRAM=dg4db2)
   )
   (SID_DESC=
      (SID_NAME=dg4db22)
      (ORACLE_HOME=oracle_home_directory)
      (PROGRAM=dg4db2)
   )
   (SID_DESC=
      (SID_NAME=dg4db23)
      (ORACLE_HOME=oracle_home_directory)
      (PROGRAM=dg4db2)
   )
)

where, oracle_home_directory is the directory where the gateway resides.

14.7.3 Multiple DRDA Databases Example: Stopping and Starting the Oracle Net Listener

Perform the following steps:

  1. From the Start menu, select Settings, Control Panel and then select Services.

  2. Select the Oracle Net Listener service for the gateway.

  3. Click Stop.

  4. Click Start.

14.7.4 Multiple DRDA Databases Example: Configuring Oracle Database for Gateway Access

Add two connect descriptor entries to the tnsnames.ora file. You must have an entry for each gateway instance, even if the gateway instances access the same database.

This example describes how to configure Oracle Net on the Oracle database for multiple gateway instances. It shows the entry for the original installed gateway first, followed by the two entries for the new gateway instances:

old_db_using=(DESCRIPTION=
              (ADDRESS=
                (PROTOCOL=TCP)
                (PORT=port_number)
                (HOST=host_name))
                (CONNECT_DATA=
                    (SID=dg4db2))
               (HS=OK))
new_db2_using=(DESCRIPTION=
              (ADDRESS=
                (PROTOCOL=TCP)
                (PORT=port_number)
                (HOST=host_name))
                (CONNECT_DATA=
                    (SID=dg4db22))
                (HS=OK))
new_db3_using=(DESCRIPTION=
              (ADDRESS=
                (PROTOCOL=TCP)
                (PORT=port_number)
                (HOST=host_name))
                (CONNECT_DATA=
                    (SID=dg4db23))
                (HS=OK)) 

The value for PORT is the TCP/IP port number of the Oracle Net Listener that is listening for the gateway. The number can be found in the listener.ora file used by the Oracle Net Listener. The value for HOST is the name of the machine on which the gateway is running. The name also can be found in the listener.ora file used by the Oracle Net Listener.

14.7.5 Multiple DRDA Databases Example: Accessing DB2 Data

Enter the following to create a database link for the dg4db22 gateway:

SQL> CREATE PUBLIC DATABASE LINK DRDA2 CONNECT TO
  2  "user2" IDENTIFIED BY "password2" USING 'new_db2_using';

Enter the following to create a database link for the dg4db23 gateway:

SQL> CREATE PUBLIC DATABASE LINK DRDA3 CONNECT TO
  2  "user3" IDENTIFIED BY "password3" USING 'new_db3_using';

After the database links are created, you can verify the connection to the new DRDA databases, as in the following:

SQL> SELECT * FROM ALL_USERS@DRDA2;
SQL> SELECT * FROM ALL_USERS@DRDA3;