Category: REXX

Testing online COBOL environments

I often use web-based environments, to test the syntax of particular statements in programing languages. As a fun challenge, I decided to see if I could find a web-based environment to test COBOL code. I was expecting this to be an impossible quest because; “why would you?” 😊

After trying a couple of sites, I landed on tutorials point’s web site:
Tutorialspoint online COBOL compiler

Using this website, I was able to write a simple COBOL program to reverse a string. Some of the key concepts used are
a. PERFORM VARYING
b. One dimensional table
c. Reference modification, aka COBOL speak for substring

Below is a screen shot of the web interface. The source code is displayed in the left panel. When you press the execute button, the right panel is a terminal that accepts input and displays output.

Occasionally the web interface displays its true unix/php identity with a message such as:

This can be remediated by putting the string in quotes as shown below:

The complete source code in text is below:

IDENTIFICATION DIVISION.
PROGRAM-ID. REVERSESTRING.

DATA DIVISION.

WORKING-STORAGE SECTION.
01  GENERAL-VARIABLES.
    05  WS-ORIGINAL-TXT           PIC X(100).
    05  WS-REVERSE-TXT-TABLE.
        10  WS-REVERSE-TXT-ITEM   PIC X(1) OCCURS 100 TIMES.
    05  WS-I                      PIC S9(3)  USAGE IS COMP-3 VALUE 0.
    05  WS-J                      PIC S9(3)  USAGE IS COMP-3 VALUE 0.
    05  WS-TEMP                   PIC X(01).
    05  WS-ORIG-TXT-LEN           PIC S9(3)  USAGE IS COMP-3.

PROCEDURE DIVISION.
    DISPLAY "Enter a string to reverse: "
    ACCEPT WS-ORIGINAL-TXT

    PERFORM VARYING WS-I FROM 100 BY -1 UNTIL ( WS-I = 1 OR WS-TEMP <> ' ')
            MOVE WS-ORIGINAL-TXT(WS-I:1) TO WS-TEMP
    END-PERFORM
    COMPUTE  WS-ORIG-TXT-LEN = WS-I + 1
    DISPLAY "You entered    : " WS-ORIGINAL-TXT(1:WS-ORIG-TXT-LEN)

    PERFORM VARYING WS-I FROM WS-ORIG-TXT-LEN BY -1 UNTIL (WS-I = 0)
            COMPUTE WS-J = WS-J + 1
            MOVE WS-ORIGINAL-TXT(WS-I:1) TO  WS-REVERSE-TXT-ITEM(WS-J)
    END-PERFORM
    
    DISPLAY "Reverse string : " WS-REVERSE-TXT-TABLE
    
    STOP RUN.

REXX RC=1 SQLSTATE=01506 on DSNREXX PREPARE statement after migrating to DB2 12

A colleague had a REXX process in place that had been working with DB2 11. After the upgrade to DB2 12, the REXX exec started failing with RC=1 on a PREPARE statement. The SQL statement being prepared contained logic to generate the boundaries used in the predicates referencing a time stamp column in a table:

  FROM creator.table_name       
WHERE TIME_STAMP_COL BETWEEN             
      'EndTS' - 2 HOURS-01 MONTHS  
  AND 'EndTS' + 2 HOURS-01 MONTHS  
   OR TIME_STAMP_COL BETWEEN             
      'EndTS' - 2 HOURS-02 MONTHS  
  AND 'EndTS' + 2 HOURS-02 MONTHS  
   OR TIME_STAMP_COL BETWEEN             
      'EndTS' - 2 HOURS-03 MONTHS  
  AND 'EndTS' + 2 HOURS-03 MONTHS  
   OR TIME_STAMP_COL BETWEEN             
      'EndTS' - 2 HOURS-04 MONTHS  
  AND 'EndTS' + 2 HOURS-04 MONTHS  
GROUP BY DATE(TIME_STAMP_COL)

The REXX code PREPAREs this statement with

address DSNREXX "EXECSQL PREPARE S40 FROM :SQL"

In DB2 11, this would return RC=0. After the upgrade to DB2 12, this started returning RC=1. The SQLCA contained:

SQLCODE = 0
SQLERRD.1 = 0
SQLERRD.2 = 0
SQLERRD.3 = 999
SQLERRD.4 = 1142028335
SQLERRD.5 = 0
SQLERRD.6 = 0
SQLWARN.1 =
SQLWARN.2 =
SQLWARN.3 =
SQLWARN.4 = 
SQLWARN.5 =           
SQLWARN.6 = W
SQLWARN.7 =  
SQLWARN.8 =
SQLWARN.9 =
SQLWARN.10 =          
SQLERRP = DSN
SQLSTATE = 01506 <---
SQLERRMC =

Per IBM

01506 = An adjustment was made to a DATE or TIMESTAMP value to correct an invalid date resulting from an arithmetic operation.

The issue was caused because the SQL would generate an invalid date for February. In the past, the PREPARE would have ignored this.

Use Rexx to create more flexible IF logic in JCL

Sometimes in JCL, there is a need to have a more flexible logic to see condition codes. Examples include:  day of week, day of month, hour, datacenter, etc.  The attached Rexx program gives a format to build IF logic based on anything.  We have also used it set condition codes if a task/job is running or if a task/job is not running.

REX Set JCL CC based on REXX IF (eg. day, hour, etc)

Author: Jim Poole
Mainframe database administrator at a large telecommunications company. Over 40 years experience.