How to read records from flat file in reverse order through
COBOL program?
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Answer / srini
Sort the file based on key in descending order. You can
read the file in reverse order.
| Is This Answer Correct ? | 44 Yes | 27 No |
Answer / shrik
Reading the records into a buffer (array) and using it in
reverse order would be the first idea that comes to mind but
that way doesnt work for file with millions of records.
| Is This Answer Correct ? | 18 Yes | 6 No |
Answer / satty
we can read file in reverse order by using a dynamic array.
first transfer the ps into array and read it by -1 from
counter = no of records in the file
| Is This Answer Correct ? | 7 Yes | 3 No |
Answer / mahendra.ch
first we can move the records to an occurs
then
we can solve this problem by using perform varing 1 by -1
until i=0
hear i = number of racords.
iam shure it works.
thank you....
| Is This Answer Correct ? | 8 Yes | 4 No |
//STEP0100 EXEC PGM=SORT
//SYSOUT DD SYSOUT=*
//SORTIN DD DSN=YOUR INPUT DATASET,DISP=SHR
//SORTOUT DD DSN=YOUR OUTPUT FILE IN REVERSE ORDER,
// DISP=(NEW,CATLG,DELETE),UNIT=SYSDA,
// SPACE=(CYL,(X,Y),RLSE)
//SYSIN DD *
INREC FIELDS=(1,80,SEQNUM,8,ZD)
SORT FIELDS=(81,8,ZD,D)
OUTREC FIELDS=(1,80)
/*
| Is This Answer Correct ? | 4 Yes | 0 No |
Answer / laxmaiah
i have some knowledge in flat files,
(open input file-name reversed)
in this type use read the data in reverse order
AND write another file
| Is This Answer Correct ? | 16 Yes | 13 No |
Answer / pa
Being a flat file, we cant be sure that it will have a unique key field. So, External to the cobol program , using SORT utility, we can add a serial no column, and then SORT it in descending order based on that column and read the file sequentially in COBOL program.
| Is This Answer Correct ? | 2 Yes | 0 No |
1. Using FileAid
//STEP0100 EXEC PGM=FILEAID
//SYSPRINT DD SYSOUT=*
//DD01 DD DSN=YOUR INPUT DATASET,DISP=SHR
//DD01O DD DSN=YOUR OUTPUT FILE IN REVERSE ORDER,
// DISP=(NEW,CATLG,DELETE),UNIT=SYSDA,
// SPACE=(CYL,(X,Y),RLSE)
//SYSIN DD *
$$DD01 COPYBACK
/*
| Is This Answer Correct ? | 1 Yes | 0 No |
Answer / sravani
using rrds it is possible. we can count the no of records using rrds key. by using if we can decrement from last to first
| Is This Answer Correct ? | 0 Yes | 7 No |
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