Tutorial: DSNREXX

Prerequisites

To complete this tutorial, you need the following software in addition to Enterprise Developer:

• IBM's DB2 Database for Linux, UNIX, and Windows (LUW). See Additional Software Requirements on Windows for more information. You can download a version of DB2 to use in the tutorial from IBM's website - click here.
• Windows Software Development Kit (SDK) installed for your version of Windows. You can download the Windows 10 SDK from the Windows Dev Center website - click here.

Installing DB2

For the purposes of this tutorial you can install a copy of DB2 Express-C. The following points can help you install DB2 for use in this tutorial:

1. When prompted in the installation setup, select the typical installation type.
2. You do not need to save your settings in a response file but this may be useful when using DB2 in future.
3. Use the default installation directory.
4. Leave the default settings when you select the IBM SSH server installation folder and startup option.
5. Always secure your DB2 administration server with a strong password.
6. You do not need to configure the DB2 instances, use the default instance configuration.

Creating a DB2 LUW sample database

Catalog the sample database as an ODBC data source

If your sample database has not been cataloged as an ODBC data source, then perform the following steps:

1. From your Windows desktop, click Start or use the shortcut keys Ctrl+Esc. In the search field, type ODBC.
2. In the search results list, select ODBC Data Source Administrator (32-bit) or ODBC Data Sources (32-bit), depending on your version of Windows.

   This opens the 32-bit version of the ODBC Data Source Administrator tool.

3. Click System DSN tab.
4. Click Add.

   This opens the Create New Data Source dialog box.

5. Click IBM DB2 ODBC DRIVER.
6. Click Finish.

   This opens the ODBC IBM DB2 Driver - Add dialog box.

7. In the Data source name field, type SAMPLE
8. In the Database alias list, select the SAMPLE database.
   • Optionally, in the Description field, type a description for your data source.
9. Click OK, and then click OK.

Create an ODBC XA switch module

1. Start an Enterprise Developer command prompt (32-bit) by clicking Run as administrator.
2. Change to the %ProgramFiles(x86)%\Micro Focus\Enterprise Developer\src\enterpriseserver\xa directory.
3. Enter build odbc
   Note: Make a note of the switch module name created, it is used in subsequent steps.

Create a working directory for your project

1. Create the working directory on your machine, for example C:\Users\Public\REXXSAMPLE
2. Create a REXX subdirectory.

Create an MSS project

1. In Visual Studio, click File > New > Project.
2. In the Create a new project dialog box, select COBOL from the Language drop-down list.
3. Select Mainframe Subsystem Application.
4. Click Next.
5. Specify REXXJCL as the project name.
6. In the Location field, specify the working directory, for example C:\Users\Public\REXXSAMPLE
7. Ensure that Place solution and project in the same directory is checked.
8. Click Create.

Add a JCL file to run DSNREXX

You can use the IKJEFT01 or IRXJCL utility to run REXX exec statements. The following JCL jobstream runs the REXX script named Test1:

1. In Solution Explorer, right-click your project.
2. Click Add > New Item.

   This opens the Add New Item - REXXJCL dialog box.

3. Expand Installed > COBOL > Native > Mainframe Subsystem.
4. Click JCL File.
5. In the Name field, type Test1.jcl.
6. Click Add.
7. In the Test1.jcl file, paste the following code:

   //REXXTEST JOB 'TEST DSNREXX SUPPORT',CLASS=A,MSGCLASS=A 
   //*
   //* Test the REXX engine using IKJEFT01
   //*
   //STEP10 EXEC PGM=IKJEFT01
   //SYSEXEC  DD DSN=USER.TEST.EXEC,DISP=SHR
   //SYSTSIN  DD *
   Test1
   //SYSPRINT DD SYSOUT=*
   //SYSTSPRT DD SYSOUT=*
   //SYSOUT   DD SYSOUT=*
   //*
   //* Test the REXX engine using IRXJCL
   //*
   //STEP20   EXEC PGM=IRXJCL,PARM='Test1'
   //SYSEXEC   DD DSN=USER.TEST.EXEC,DISP=SHR
   //SYSTSPRT  DD SYSOUT=*
   //SYSTSIN   DD DUMMY
   

8. Click File > Save Test1.jcl.

Create an MSS-enabled Enterprise Server

Now you want to create an enterprise server region with Mainframe Subsystem (MSS) for JCL use:

1. In Solution Explorer, right-click your project.
2. Click Enterprise Server > New Enterprise Server.
   This opens the Create New Enterprise Server dialog box.

   Note: If you are prompted with an Enterprise Server Sign On dialog box, click OK without specifying any sign-on details. This is a standard security dialog box.
3. In the Name field, type REXX32
4. Click Browse next to the Template field.
5. Click JCLTemplate.
6. Click Open.
7. Click OK.

Add an XA resource for REXX procedures pointing to the DB2 LUW SAMPLE database

Now that the enterprise server region is created, you need to set up an XA resource:

1. In Server Explorer, right-click Micro Focus Servers.
2. Click Administration.
3. Click Edit next to the REXX32 region name.
4. Click Server > Properties > XA Resources.
5. Click Add.
6. In the ID field, type DB2T
7. In the Name field, type REXXPROC
8. In the Module field, type the location and name of the ODBC XA switch module created in the earlier steps, for example:

   C:\Program Files (x86)\Micro Focus\Enterprise Developer\src\enterpriseserver\xa\ESODBCXA.dll

   Note: When specifying the location and name of the ODBC XA switch module, do not enter an environment variable such as %ProgramFiles(x86)%. Ensure that you use an expanded path.
9. In the Open string field, type DSN=SAMPLE

   Where SAMPLE is the Data source name specified in the ODBC Data Source Administrator.

   • You may need to add the ID and PASSWORD if connecting to a remote database. See Generic one-phase commit for ODBC xa_open string for more information.
10. Click Add.

See To define an XA resource (XAR) for an enterprise server region for more information.

Start the enterprise server region

1. In Server Explorer, expand Micro Focus Servers and then localhost.
2. Right-click REXX32, and then click Start.
   Note: The Enterprise Server Sign On dialog box might prompt you to provide connection details for the server. This is a standard security dialog box. Click OK without specifying any sign-on details. Also, if prompted to disable password recovery, click No.
   • If you receive a Windows Security Alert for the MF Communications Process, click Allow access.

Catalog the directories that have the REXX procedures

You need to specify the catalog file that holds details of the data sets required by the JCL job that run in an enterprise server region. To do this you need to create a Dynamic PDS. See Dynamic PDSs for more information.

1. In Server Explorer, right-click REXX32 under localhost.
2. Click Show Catalog.
3. Click List.
4. Click New.
5. In the DS Name field, type USER.TEST.EXEC
6. In the Physical File field, type C:\Users\Public\REXXSAMPLE\REXX
7. From the DS Org list, select PO.
8. From the RECFM list, select LSEQ.
9. Check Dynamic PDS.
10. In the PDS Exts field, type rex
11. Click Apply.

Copy the REXX script from the samples directory

1. Copy the Test1.rex file, from the %PUBLIC%\Documents\Micro Focus\Enterprise Developer\Samples\Mainframe\SQL\OpenESQL\DSNREXX\Test1\Scripts sample directory to the C:\Users\Public\REXXSAMPLE\REXX directory.

To run the JCL job

1. In Solution Explorer, expand the project to show the Test1.jcl file.
2. Right-click the Test1.jcl file, and then click Submit JCL.

View the spool output

You can check the result of submitting the JCL job by viewing the spool:

1. In Server Explorer, expand Micro Focus Servers > localhost.
2. Right-click REXX32.
3. Click Show Spool.
4. Click REXXTEST.

   This provides more information on the job submitted.

5. Click SYSTSPRT for either of the steps to see more information.
   The following message or similar is displayed for STEP10:

                                                                                                                              
   DROPPING REXTEST1 TABLE                                                                                                               
   INSERTING DATA                                                                                                                        
   PREPARING S1                                                                                                                          
   FETCHING DATA                                                                                                                         
   TEST PASSED  -33329.3333                                                                                                              
   INSERTING DATA USING INSQLDA                                                                                                          
   PREPARING S3                                                                                                                          
   FETCHING DATA USING OUTSQLDA                                                                                                          
   TEST PASSED  -33329.3333