|
View previous topic :: View next topic
|
| Author |
Message |
swathi.a
Warnings : 1
New User
Joined: 05 Feb 2007
Posts: 10
Location: hyd
|
|
|
|
Hi...
How to rewrite/update a particular record in a sequential file......... i have 5 records in a file & i have to update the 3rd record ....
(organisation & access is sequential)
Thx in advance.. |
|
| Back to top |
|
 |
guptae
Moderator
Joined: 14 Oct 2005
Posts: 1208
Location: Bangalore,India
|
|
|
|
Hi There,
U can use
| Code: |
OPEN I-O IN-FILE
:
READ IN-FILE
MOVE 1 TO WS-CNT
PERFORM UNTIL END-OF-FILE OR WS-CNT=4
IF WS-CNT = 3
Update the record
REWRITE RECORD-IN
END-IF
ADD 1 TO WS-CNT
READ IN-FILE
END-PERFORM |
|
|
| Back to top |
|
|
swathi.a
Warnings : 1
New User
Joined: 05 Feb 2007
Posts: 10
Location: hyd
|
|
|
|
hi.
i read in the document that if we want to rewrite a record in a sequential file we have to write a read statement before that rewrite statement & if we do so it will rewrite the first record irrespective of the condition. |
|
| Back to top |
|
|
guptae
Moderator
Joined: 14 Oct 2005
Posts: 1208
Location: Bangalore,India
|
|
|
|
Hi swathi,
Its not like that it will rewrite the record which is pointed by file-pointer |
|
| Back to top |
|
|
donevin
New User
Joined: 07 Jun 2005
Posts: 70
Location: South Africa
|
|
|
|
| I don't think rewrite is supported for line sequential files 'cause it cannot be opened in I-O mode and it doesn't have a key. Therefore you will have to (1) Read from input file (2) have same attribute file open as output (3) write to output unchanged records (4) change record three as required in working storage (5) write changed record to output (6) repeat (1) - (3) 'till end. |
|
| Back to top |
|
|
William Thompson
Global Moderator
Joined: 18 Nov 2006
Posts: 3156
Location: Tucson AZ
|
|
|
|
| donevin wrote: |
| I don't think rewrite is supported for line sequential files 'cause it cannot be opened in I-O mode |
The Fine Manual:
| Quote: |
| The I-O phrase is not valid for line-sequential files. |
Donevin,
Do you know what a line-sequential file is? |
|
| Back to top |
|
|
prav_06
Warnings : 1
Active User
Joined: 13 Dec 2005
Posts: 154
Location: The Netherlands
|
|
|
|
| Quote: |
Donevin,
Do you know what a line-sequential file is? |
And this is wat u get from Bill if ya go wrong 
Donevin,
A line sequential file can be opened in I-O mode, output mode, Extend mode and of course input mode.
And for Swathi,
| Quote: |
| i read in the document that if we want to rewrite a record in a sequential file we have to write a read statement before that rewrite statement & if we do so it will rewrite the first record irrespective of the condition. |
U r absolutely rite, but before re-write u should position the cursor to the appropriate record, check this example
READ IN-FILE.
IF IN-REC-KEY = 100
Move To inrec variable
Move To inrec variable
Rewrite IN-REC.
This piece of code shd be in a loop to check for all the records in a Seq. File .
Cheer's,
Thamilzan. |
|
| Back to top |
|
|
William Thompson
Global Moderator
Joined: 18 Nov 2006
Posts: 3156
Location: Tucson AZ
|
|
|
|
| prav_06 wrote: |
| A line sequential file can be opened in I-O mode, output mode, Extend mode and of course input mode. |
OK, then please explain this, the
Enterprise COBOL for z/OS and OS/390 Language Reference; 6.2.26 OPEN statement clearly states:
| Quote: |
I-O
Permits opening the file for both input and output operations. The I-O phrase can be specified only for files assigned to direct access devices.
The I-O phrase is not valid for line-sequential files.
|
|
|
| Back to top |
|
|
donevin
New User
Joined: 07 Jun 2005
Posts: 70
Location: South Africa
|
|
|
|
| Right back at ya prav_06. I don't want to bicker about this remove the line from my line sequential post and yes I know what line sequential files are. |
|
| Back to top |
|
|
swathi.a
Warnings : 1
New User
Joined: 05 Feb 2007
Posts: 10
Location: hyd
|
|
|
|
| prav_06 wrote: |
| Quote: |
Donevin,
Do you know what a line-sequential file is? |
And this is wat u get from Bill if ya go wrong
Donevin,
A line sequential file can be opened in I-O mode, output mode, Extend mode and of course input mode.
And for Swathi,
| Quote: |
| i read in the document that if we want to rewrite a record in a sequential file we have to write a read statement before that rewrite statement & if we do so it will rewrite the first record irrespective of the condition. |
U r absolutely rite, but before re-write u should position the cursor to the appropriate record, check this example
READ IN-FILE.
IF IN-REC-KEY = 100
Move To inrec variable
Move To inrec variable
Rewrite IN-REC.
This piece of code shd be in a loop to check for all the records in a Seq. File .
Cheer's,
Thamilzan. |
if i dont know the key value how will it work.
i have a pgm with 2 files where i compare the emp-number of 1st record in the 1st file with all the records in the 2nd file. if it is found then i have to rewrite that record... |
|
| Back to top |
|
|
William Thompson
Global Moderator
Joined: 18 Nov 2006
Posts: 3156
Location: Tucson AZ
|
|
|
|
| swathi.a wrote: |
if i dont know the key value how will it work.
i have a pgm with 2 files where i compare the emp-number of 1st record in the 1st file with all the records in the 2nd file. if it is found then i have to rewrite that record... |
There is no key, just read until you find the record that you want to update, update the record and rewrite it.
Simple  |
|
| Back to top |
|
|
guptae
Moderator
Joined: 14 Oct 2005
Posts: 1208
Location: Bangalore,India
|
|
|
|
Hi there,
First sort both the files on the basis of emp-number then
| Code: |
Read filea
Read fileb
perform until end-of-filea
if emp-num of filea =emp-num of file b
update the record
rewrite fileb
read filea
read fileb
else
if emp-num of filea < emp-num of fileb
read filea
else
read fileb
end-if
end-if
end-perform |
|
|
| Back to top |
|
|
swathi.a
Warnings : 1
New User
Joined: 05 Feb 2007
Posts: 10
Location: hyd
|
|
|
|
| what does "update the record" mean...is it jus a comment or a statement... |
|
| Back to top |
|
|
guptae
Moderator
Joined: 14 Oct 2005
Posts: 1208
Location: Bangalore,India
|
|
|
|
Hi swati ,
Its just a comment befor rewriting u want to do some changes in the record thats why u r rewriting.
Hope it's clear now |
|
| Back to top |
|
|
swathi.a
Warnings : 1
New User
Joined: 05 Feb 2007
Posts: 10
Location: hyd
|
|
|
|
| thx ekta..i'll try it & i'll get back to u if i dont get.... |
|
| Back to top |
|
|
dick scherrer
Moderator Emeritus
Joined: 23 Nov 2006
Posts: 19244
Location: Inside the Matrix
|
|
|
|
Hello,
If you want to be really sure that your code will work in your environment with your specific file definition, you might make a copy of the file then put together a VERY small program that will attempt to read the existing records and re-write them with some constant value - no matching files or any computations.
When the run ends (or abends) look in the test file and see what has happened. If you isloate testing the re-write you will not have to concern yourself with any of the other processing the "real" program needs to do. You will see how re-write works for your situation. |
|
| Back to top |
|
|
swathi.a
Warnings : 1
New User
Joined: 05 Feb 2007
Posts: 10
Location: hyd
|
|
|
|
| guptae wrote: |
Hi there,
First sort both the files on the basis of emp-number then
| Code: |
Read filea
Read fileb
perform until end-of-filea
if emp-num of filea =emp-num of file b
update the record
rewrite fileb
read filea
read fileb
else
if emp-num of filea < emp-num of fileb
read filea
else
read fileb
end-if
end-if
end-perform |
|
Hi,
rewrite in this way is not working...
its not giving any error and also its not updating the file... |
|
| Back to top |
|
|
William Thompson
Global Moderator
Joined: 18 Nov 2006
Posts: 3156
Location: Tucson AZ
|
|
|
|
| swathi.a wrote: |
rewrite in this way is not working...
its not giving any error and also its not updating the file... |
How do you know it's not updating?
Post your code. |
|
| Back to top |
|
|
swathi.a
Warnings : 1
New User
Joined: 05 Feb 2007
Posts: 10
Location: hyd
|
|
|
|
| Code: |
MOVE EMP-NUMBERT TO EMP-NUMBER1
MOVE BASIC-PAYT TO BASIC-PAY1
MOVE HOUSE-ALLOWT TO HOUSE-ALLOW1
MOVE CONVEY-ALLOWT TO CONVEY-ALLOW1
MOVE DESG-CODET TO DESG-CODE1
COMPUTE HOUSE-ALLOW2 = 0.5 * BASIC-PAY1
COMPUTE CONVEY-ALLOW2 = 0.3 * BASIC-PAY1
IF CONVEY-ALLOW2 < 2500
MOVE 2500 TO CONVEY-ALLOW2
ELSE IF CONVEY-ALLOW2 > 6000
MOVE 6000 TO CONVEY-ALLOW2
END-IF
DISPLAY CONVEY-ALLOW2
IF EMP-NUMBER1 > 100001 AND EMP-NUMBER1 IS <= 999999
IF DESG-CODE1 > 01 AND DESG-CODE1 IS <= 15
IF BASIC-PAY1 > 5000 AND BASIC-PAY1 IS <= 15000
IF HOUSE-ALLOW1 = HOUSE-ALLOW2 AND
CONVEY-ALLOW1 = CONVEY-ALLOW2
MOVE TRANS-FILE TO EMP-FILE
[b]RE-WRITE EMP-FILE [/b]
ELSE
MOVE TRANS-FILE TO EMP-FILE
MOVE CONVEY-ALLOW2 TO CONVEY-ALLOW
MOVE HOUSE-ALLOW2 TO HOUSE-ALLOW
RE-WRITE EMP-FILE
END-IF
ELSE
DISPLAY "INVALID BASIC PAY "
END-IF
ELSE
DISPLAY "INVALID DESG CODE "
END-IF
ELSE
DISPLAY "INVALID EMPLOYEE NUMBER " EMP-NUMBER1
END-IF. |
This is the code i hav written for rewrite.. |
|
| Back to top |
|
|
dick scherrer
Moderator Emeritus
Joined: 23 Nov 2006
Posts: 19244
Location: Inside the Matrix
|
|
|
|
Hello,
Please do this
| Quote: |
If you want to be really sure that your code will work in your environment with your specific file definition, you might make a copy of the file then put together a VERY small program that will attempt to read the existing records and re-write them with some constant value - no matching files or any computations.
When the run ends (or abends) look in the test file and see what has happened. If you isloate testing the re-write you will not have to concern yourself with any of the other processing the "real" program needs to do. You will see how re-write works for your situation.
|
then report back on what was the outcome.
If your problem IS the "re-write" you need to isloate that and make sure that there really is a re-write problem versus some other logic problem. If you persist in testing with the whole program, you might display more information before and after the 2 places a re-write could occur (i.e the record before the moves and the record after the moves. You would not need to process the whole file - just enough to verify that both paths to the re-write were followed. Actually, if your original post was accurate there are only 5 records - so it would be easy to use them all.
From the bit of code that was posted i believe it likely that there is a logic error somwhere. How do you know the re-write code was ever executed? |
|
| Back to top |
|
|
William Thompson
Global Moderator
Joined: 18 Nov 2006
Posts: 3156
Location: Tucson AZ
|
|
|
|
| swathi.a wrote: |
| Code: |
IF BASIC-PAY1 > 5000 AND BASIC-PAY1 IS <= 15000
IF HOUSE-ALLOW1 = HOUSE-ALLOW2 AND
CONVEY-ALLOW1 = CONVEY-ALLOW2
MOVE TRANS-FILE TO EMP-FILE
RE-WRITE EMP-FILE
ELSE
MOVE TRANS-FILE TO EMP-FILE
MOVE CONVEY-ALLOW2 TO CONVEY-ALLOW
MOVE HOUSE-ALLOW2 TO HOUSE-ALLOW
RE-WRITE EMP-FILE
END-IF
|
|
Kinda looks like you are rewriting in either case from the same "trans-file", which came from where? the emp-file? |
|
| Back to top |
|
|
swathi.a
Warnings : 1
New User
Joined: 05 Feb 2007
Posts: 10
Location: hyd
|
|
|
|
| William Thompson wrote: |
| swathi.a wrote: |
| Code: |
IF BASIC-PAY1 > 5000 AND BASIC-PAY1 IS <= 15000
IF HOUSE-ALLOW1 = HOUSE-ALLOW2 AND
CONVEY-ALLOW1 = CONVEY-ALLOW2
MOVE TRANS-FILE TO EMP-FILE
RE-WRITE EMP-FILE
ELSE
MOVE TRANS-FILE TO EMP-FILE
MOVE CONVEY-ALLOW2 TO CONVEY-ALLOW
MOVE HOUSE-ALLOW2 TO HOUSE-ALLOW
RE-WRITE EMP-FILE
END-IF
|
|
Kinda looks like you are rewriting in either case from the same "trans-file", which came from where? the emp-file? |
if the conditions specified are satisfied it rewrites from trans-file to emp file...
if the house allow & convey allow conditions are not satisfied, it writes from trans-file to emp-file with corrected house allow & convey-allow.. |
|
| Back to top |
|
|
h.dinesh
New User
Joined: 06 Dec 2006
Posts: 46
Location: Chennai
|
|
|
|
Swati,
Did you check if any of these 'DISPLAY' worked? Just to check if there is any problem with the logic or not.
| Code: |
ELSE
DISPLAY "INVALID BASIC PAY "
END-IF
ELSE
DISPLAY "INVALID DESG CODE "
END-IF
ELSE
DISPLAY "INVALID EMPLOYEE NUMBER " EMP-NUMBER1
END-IF. |
Also check the variables used
CONVEY-ALLOW &
HOUSE-ALLOW
before second rewrite are correct.
Dinesh |
|
| Back to top |
|
|
|
|
