💬 Q&A Solutions

COND Parameter:

• Tests return codes from previous steps
• Bypasses step if condition is TRUE
• Works opposite to programming logic!
• COND=(4,LT) means: Skip if 4 < any previous RC

IF/THEN/ELSE:

• More intuitive programming-like syntax
• Executes steps when condition is TRUE
• Supports AND, OR operators
• Can check ABEND conditions

Example:

// Using COND (skip if RC < 4)
//STEP2 EXEC PGM=PROG2,COND=(4,LT)

// Using IF/THEN/ELSE
//    IF STEP1.RC = 0 THEN
//STEP2 EXEC PGM=PROG2
//    ELSE
//ERROR EXEC PGM=ERRPROC
//    ENDIF

Pseudo-conversational programming is a technique where the program ends between user interactions, freeing system resources.

How it works:

1. Program sends screen to user and ends (RETURN TRANSID)
2. User enters data and presses Enter
3. CICS starts a new task with same program
4. Program retrieves saved data from COMMAREA
5. Process continues

Benefits:

• Efficient resource usage
• Better response times
• More concurrent users

Implementation:

* End task, wait for user
EXEC CICS RETURN
    TRANSID('MENU')
    COMMAREA(WS-COMM)
    LENGTH(100)
END-EXEC.

* On return, check EIBCALEN
IF EIBCALEN = 0
    PERFORM FIRST-TIME
ELSE
    MOVE DFHCOMMAREA TO WS-COMM
    PERFORM PROCESS-INPUT
END-IF.

SQLCODE is a return code in SQLCA indicating the result of SQL execution.

Common SQLCODE values:

Negative = Error, 0 = Success, 100 = No data

INNER JOIN:

• Returns only matching rows from both tables
• If no match, row is excluded

LEFT OUTER JOIN:

• Returns all rows from left table
• Matching rows from right table
• NULL for right table if no match

-- INNER JOIN
SELECT E.NAME, D.DEPT_NAME
FROM EMPLOYEE E
INNER JOIN DEPARTMENT D
ON E.DEPT_ID = D.DEPT_ID;

-- LEFT OUTER JOIN
SELECT E.NAME, D.DEPT_NAME
FROM EMPLOYEE E
LEFT OUTER JOIN DEPARTMENT D
ON E.DEPT_ID = D.DEPT_ID;

Use LEFT JOIN when you want all employees even those without department.

COMMAREA (Communication Area) is used to pass data between programs or between transactions in pseudo-conversational programming.

Uses:

• Pass data between LINK/XCTL programs
• Save data between pseudo-conversational transactions
• Maximum size: 32KB

How it works:

1. Calling program: COMMAREA option on LINK/XCTL/RETURN
2. Called program: DFHCOMMAREA in LINKAGE SECTION
3. Check EIBCALEN for length (0 = no COMMAREA)

* Calling program
EXEC CICS LINK
    PROGRAM('SUBPROG')
    COMMAREA(WS-DATA)
    LENGTH(100)
END-EXEC.

* Called program
LINKAGE SECTION.
01 DFHCOMMAREA PIC X(100).

IF EIBCALEN > 0
    MOVE DFHCOMMAREA TO WS-DATA
END-IF.