differnce between read work file 1 and read work file once?
why we are using work file once?
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Answer / niki
Both used to read sequentila file.
Read work file 1:
1. is a processing loop strating like:
Read work file 1 file1
---
--
--
end- work.
Here ---> file 1 is file name here and 1 is arbitary file
number which is translated into dataset names CMwk01 in jcl.
read work file once:
1. Reads only one reacord is to be read.
2. there is no processing loop
eg. Read work file once
do correct me if i am wrong?
| Is This Answer Correct ? | 8 Yes | 0 No |
Answer / satya
To answer why do we use READ WORK FILE 1 ONCE
It is generally used when you specifically want to know if
the input file is empty programatically and if you would
like to handle the way you wanted if the file is empty,just
like below,
READ work 1 ONCE #WORK
AT END OF FILE
Write "Input empty"
terminate 99
END-ENDFILE
this piece of code can be placed at the begining of your
program and this helps to avoid unnecessary entry into
programming statements with empty file in input, unless
expected
| Is This Answer Correct ? | 7 Yes | 1 No |
Answer / kevin
As NIKI stated the read work file 1 is identifying the work
file in JLC
As for the work read work file once it is used to get the
next record. The record pointer doesn't get reset allow
you to process records from 2 files one at at time.
For example if you are comparing record from 2 work files
and processing the records in order
read work a once /* reads the first a record
read work b once /* reads the second b record
REPEAT
IF rec-a > rec-b
process b ...
read work b once
escape top
End-if
IF rec-a < rec-b
process a ...
read work a once
ecape top
End-if
If rec-a = rec-b
process a and b ...
read work a once
read work b once
end-if
end-repeat
(of course you would need escape logic in the loop such as
end of file logic...)
| Is This Answer Correct ? | 2 Yes | 0 No |
Answer / nisha
Read Work file 1
Will read dataset details defined as CMWRK01 from JCL.
Read work file once
Will read first record from the input file
| Is This Answer Correct ? | 1 Yes | 0 No |
COuld you please let me know along with a sample on how are you going to remove duplicates from the file that is being read. Thanks Sam
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