Just like “EVALUATE WHEN” in Cobol, “Switch Case” in C, Easytrieve has got its equivalent “CASE WHEN” statement.
And, the when statement is not only capable of validating one particular value, it can also validate a range of values.
See the below sample Easytrieve program, which is self explanatory.
CASE WS-NUM
WHEN 1
DISPLAY 'ONE'
WHEN 2
DISPLAY 'TWO'
WHEN 3 THRU 99
DISPLAY '3 TO 99'
END-CASE
A complete program will look like,
----+----1----+----2----+----3----+----4----+----5----+----6----+----7--
LIST ON
FILE FILE1
WS-DAY W 2 N
JOB INPUT NULL
WS-MONTH = 5
CASE WS-MONTH
WHEN 1
DISPLAY 'SUNDAY'
WHEN 2
DISPLAY 'MONDAY'
WHEN 3
DISPLAY 'TUESDAY'
WHEN 4
DISPLAY 'WEDNESDAY'
WHEN 5
DISPLAY 'THURSDAY'
WHEN 6
DISPLAY 'FRIDAY'
WHEN 7
DISPLAY 'SATURDAY'
END-CASE
STOP
Declaring VSAM:
Reading VSAM file by Key
----+----1----+----2----+----3----+----4----+----5----+----6----+----7--
LIST ON
FILE FILE1 FB(80 200)
IN-REC 1 80 A
IN-KEY 1 8 A
FILE FILE2 VS
F2-REC 1 80 A
F2-KEY 1 8 A
F2-VALUE 15 30 A
FILE OUTFILE FB(80 200)
OUT-REC 1 80 A
OUT-KEY 1 8 A
OUT-VALUE 10 30 A
JOB INPUT NULL
GET FILE1
DO WHILE NOT EOF INFILE
READ FILE2 KEY IN-KEY STATUS
IF FILE2 : STATUS EQ 0
MOVE IN-KEY TO OUT-KEY
MOVE F2-VALUE TO OUT-VALUE
PUT OUTFILE
ELSE
DISPLAY IN-KEY ' NOT PRESENT IN VSAM FILE'
END-IF
GET INFILE
END-DO
STOP
Arithmetic operations:
* Assignment
WS-TEMP = 10
* Addition
WS-TEMP = WS-TEMP + 2
* Subtraction
WS-TEMP = WS-TEMP - WS-TEMP2
* Multiplication
WS-TEMP = 10 * -5
* Division
WS-TEMP = WS-TEMP / 5
Logical operators:
| Equal |
IF WS-NUMBER EQ 12345 |
| Not Equal |
IF WS-NUMBER NE 11111 |
| Checking range A through B |
IF WS-NUMBER EQ 11111 THRU 22222 |
| Checking a variable for Numeric |
IF WS-NUMBER2 NUMERIC |
| Checking for Zeros |
IF WS-NUMBER NOT ZEROS |
The Below Rexx function STRREPLACE can replace a part of a string with a new one
/*REXX*/
MYSTR = 'MY TEST STRING'
SAY MYSTR
MYSTR = STRREPLACE(MYSTR,"TEST","NEW")
SAY MYSTR
EXIT
/* A FUNCTION TO DO A STRING REPLACE */
STRREPLACE:
ORIGINAL = ARG(1)
OLDTXT = ARG(2)
NEWTXT = ARG(3)
NEWSTR = ORIGINAL
DO WHILE POS(OLDTXT,NEWSTR) > 0
NEWSTR = SUBSTR(NEWSTR, 1 , POS(OLDTXT,NEWSTR)-1) ||,
NEW || SUBSTR(NEWSTR, POS(OLDTXT,NEWSTR) + LENGTH(OLDTXT))
END
RETURN NEWSTR
- A Rexx program should have a comment “/*rexx*/” in the first line
- Rexx statements are Case insensitive
- A rexx program can be executed by giving “EX” to the rexx member containing the rexx program
Hello World program
/************REXX***********/
SAY "HELLO WORLD"
EXIT
IF-ELSE in Rexx
/******REXX******/
/* EXECUTE SOME INSTRUCTIONS CONDITIONALLY */
SAY 'ENTER NUMBER LESS THEN 10 '
PULL A
IF A<10 THEN
DO
SAY "CORRECT NUMBER!!"
END
ELSE SAY "WRONG!"
EXIT
DO-Loops in Rexx
/*******REXX***********/
/* SAY "HI" 5 TIMES */
DO 5
SAY "HI"
END
/**/
DO C=1 TO 5
SAY "HI"
END
/**/
DO M=0.3 TO 1.5 BY .3
SAY "HI"
END
/* INFINITE LOOP*/
/*
DO FOREVER
SAY "HI"
END
*/
EXIT
DO WHILE and DO UNTIL
DO WHILE runs the loop all the times if the condition given validates to TRUE
DO UNTIL runs the loop all the times if the condition given validates to FALSE
/************REXX***********/
DO WHILE A = 5
SAY 'HI'
/* SOMETHING THAT MODIFIES A */
END
DO UNTIL A = 5
SAY 'HI'
/* SOMETHING THAT MODIFIES A */
END
EXIT
SELECT statement in REXX
The below code shows how to use the SELECT clause. You can also note the use of NOT Operator “\”.
/******REXX******/
/* DECIDE WHAT RANGE A NUMBER IS IN */
SAY 'ENTER A NUMBER'
PULL A
SELECT
WHEN A>0 & A<100 THEN SAY "1-99"
WHEN A\<100 & A<500 THEN SAY "100-499"
WHEN \ (A<500 | A>=1000) THEN SAY "500-29"
OTHERWISE SAY "OUT OF RANGE"
END
EXIT
Dividing one Number by another
PULL gets the value from the user.
/******REXX****************************************************/
/* DIVIDING ONE NUMBER BY ANOTHER NUMBER */
/**************************************************************/
SAY 'DIVIDING ONE NUMBER BY ANOTHER NUMBER'
SAY 'ENTER NUMERATOR:'
PULL Z
SAY 'ENTER DENOMINATOR:'
PULL N
IF N=0 THEN
SAY 'DIVISION BY ZERO'
ELSE DO
SAY 'NUM / DENOM IS' Z/N
SAY 'REST IS' Z//N
END
EXIT
A list of REXX functions can be found here.
You can also download a complete Tutorial PDF.
The syntax for a DO WHILE clause in Easytrieve is
DO WHILE CONDITION1 [ AND CONDITION2 | OR CONDITION3 ]
STATEMENTS TO EXECUTE
END-DO
Please refer the below sample of code to use a do-while clause in Easytrieve.
----+----1----+----2----+----3----+----4----+----5----+----6----+----7--
LIST ON
FILE INFILE
*
WS-COUNT W 4 N VALUE 0
*
JOB INPUT NULL
WS-COUNT = 1
DO WHILE WS-COUNT LE 15
DISPLAY ' COUNT IS ' WS-COUNT
WS-COUNT = WS-COUNT + 1
END-DO
STOP.
Let us say, I have a lookup table file for Name of the Months. (DD name LOOKUP1 in our example program)
----+----1----+----2----+----3----+----4----+----5----+----6----+----7--
01 JANUARY
02 FEBRUARY
03 MARCH
04 APRIL
05 MAY
06 JUNE
07 JULY
08 AUGUST
09 SEPTEMBER
10 OCTOBER
11 NOVEMBER
12 DECEMBER
and I have another file (DD name ACTUAL) for which the month names have to be read from the above file.
----+----1----+----2----+----3----+----4----+----5----+----6----+----7--
05
12
33
03
Output File should have the month numbers from the ACTUAL file and should have fetched the month name from LOOKUP1 file and put in the output file.
Ie,
OUTFILE
----+----1----+----2----+----3----+----4----+----5----+----6----+----7--
05 MAY
12 DECEMBER
33 INVALID MON
03 MARCH
This Can be achieved by the following program which uses the LOOKUP1 file as a table.
The field names ARG and DESC should not be changed (because those are keywords).
And also the TABLE file should not have high level group variable for the full record.
----+----1----+----2----+----3----+----4----+----5----+----6----+----7--
LIST ON
FILE LOOKUP1 TABLE
ARG 1 2 A
DESC 4 15 A
FILE ACTUAL
ACTUAL-REC 1 80 A
MONTH-LIST 1 2 A
FILE OUTFILE
OUT-REC 1 80 A
OUT-MONTH-NUM 1 2 A
OUT-MONTH-NAME 4 15 A
JOB INPUT NULL
GET ACTUAL
DO WHILE NOT EOF ACTUAL
MOVE MONTH-LIST TO OUT-MONTH-NUM
SEARCH LOOKUP1 WITH MONTH-LIST , GIVING OUT-MONTH-NAME
IF NOT LOOKUP1
MOVE 'INVALID MON' TO OUT-MONTH-NAME
END-IF
PUT OUTFILE
GET ACTUAL
END-DO
STOP.
SYSIBM.SYSSEQUENCES has a column called MAXASSIGNEDVAL, that gets assigned whenever the values for IDENTITY/SEQUENCE columns are getting generated (at least for the cache).
SELECT MAXASSIGNEDVAL
FROM SYSIBM.SYSSEQUENCES
WHERE SEQUENCEID =
(SELECT BSEQUENCEID FROM SYSIBM.SYSSEQUENCESDEP
WHERE DCREATOR = 'USER1'
AND DNAME = 'EMP_TABLE'
AND DCOLNAME = 'EMP_ID');
Declaring (Creating)
DECLARE GLOBAL TEMPORARY TABLE
SESSION.EMP_TABLE
(EMPID INTEGER NOT NULL,
EMPNAME CHAR(20))
[ON COMMIT DELETE ROWS | ON COMMIT PRESERVE ROWS]
Even if you do not give the qualifier SESSION, the table will be created as SESSION.EMP_TABLE.
Temporary tables cannot be created with our own qualifier.
Inserting
INSERT INTO SESSION.EMP_TABLE VALUES(1,'KARTHIK')
Fetching
SELECT * FROM SESSION.EMP_TABLE
Avoid duplicates in a particular field (say first 8 characters)
SORT FIELDS=(1,8,CH,A)
SUM FIELDS=NONE
Sort first 8 characters, and omit few values
SORT FIELDS=(1,8,CH,A)
OMIT COND=(1,8,CH,EQ,C'AAAAAAAA')
Sort first 8 characters, and include only few values
SORT FIELDS=(1,8,CH,A)
INCLUDE COND=(1,8,CH,EQ,C'AAAAAAAA',OR, 1,8,CH,EQ,C'BBBBBBBB')
Sort card to select only 15 characters from 36th position of my input file.
//SORTSTEP EXEC PGM=SORT
//SYSOUT DD SYSOUT=*
//SORTIN DD DISP=SHR,
// DSN=MYDSN.NAME
//SORTWK01 DD UNIT=SYSDA,SPACE=(CYL,2000)
//SORTWK02 DD UNIT=SYSDA,SPACE=(CYL,2000)
//SORTWK03 DD UNIT=SYSDA,SPACE=(CYL,2000)
//SYSIN DD *
SORT FIELDS=COPY
OUTFIL CONVERT,
OUTREC=(1:36,15,65X)
/*
//SORTOUT DD DISP=(NEW,CATLG,DELETE),
// SPACE=(CYL,(250,100),RLSE),
// UNIT=DISK,
// DCB=(RECFM=FB,LRECL=80,BLKSIZE=0),
// DSN=MYDSN.OUTPUT.NAME
The 65X is given to fill the remaining 65 bytes of the output file with spaces.
