Reading Last Record dynamically through pure COBOL program

GAFUR · New User Joined: 19 May 2005 Posts: 31

Hi ,

I want to Know how to read dyamically the LAST record of a VSAM file ie using HIGH VALUES , START , READ commands. Is it possible through COBOL? .
I am using pure COBOL program.

I dont want to use SORT at any stage.
I am not using CICS/DB2.

Thanks & regards
Gafur.

khamarutheen · Active Member Joined: 23 Aug 2005 Posts: 677 Location: NJ

Hi Gafur,
By using RBA or Key value u can use the random read option either in last or mid as u like.. it depends on u my frnd

mmwife · Super Moderator Joined: 30 May 2003 Posts: 1592

The problem w/KAK's solution is that you probably don't know the key/RBA of your last rec.

Since there's currently no way to do a read prev in a batch cobol pgm you'll have to look to assembler or a utility.

You can use FileAid to do this. Then read it into your cobol pgm as a separate file.

gowtham_1982 · Active User Joined: 02 Dec 2005 Posts: 109

hi gafur,

i guess you don't know the RBA or KEY or RRN of the file. you need to use the cobol logic.

read the file till you meet the end of file condition(check the file status for a value (ten) 10 ). then for every successful read (check the file status for zeroes) increment the count by 1.

now when the end condition is met, you have the total no of records in the file. we can read the last record by subscripting the record with the total no of records.

please note that this logic is possible only for a file with records defined with OCCURS clause

corrections welcomed...

gowtham

khamarutheen · Active Member Joined: 23 Aug 2005 Posts: 677 Location: NJ

Hi gowtham,

Ur logic is good but it will take time if there is large no. of records.

gowtham_1982 · Active User Joined: 02 Dec 2005 Posts: 109

sbalajibe · New User Joined: 15 Aug 2005 Posts: 62

Hi All,

U Cannot Use RBA in Cobol as cobol does not support RBA

move high values to the key field and read
i thing this should read last record of that key

please check

thanks and regards
Balaji

DavidatK · Posted: Fri Jan 06, 2006 4:22 am

Hi GAFUR,

The responses above are correct; there is no way of directly accessing the last record to obtain the highest key. There are, however some logics that will greatly minimize the number of I/Os to the file. Like a binary search of the INDEX using the START verb. The START verb accesses only the INDEX to set the current position in the VSAM file.
What does the description of the key look like? i.e. the ?PIC? for the key?

Lets make an assumption that your key is PIC S9(11).

mmwife · Super Moderator Joined: 30 May 2003 Posts: 1592

Gafur, it would help to know the broader aspects of the problem. What do you plan to do AFTER you read the last rec? That and perhaps other info may lead to a workable solution.

The FileAid solution would make the key of the last VSAM rec available to your pgm or you could just read the rec as a PS file after FA creates it.

Gafur, are you still out there?

GAFUR · New User Joined: 19 May 2005 Posts: 31

Hi mmwife,

Thanks for your response. But we dont have file aid in our system. Our client is using some other tool for VSAM which dont have the all options of file-aid. And also we are not allowed to edit the Batch Jcl ( for eg to use sort or other feature).

Instead of reading sequentially and inserting some cobol logic for this requirement , i thought of using HIGH VALUES. After going through all solutions provided by group then i came to know it is not possible to get Last record using high values.

Group.Thank you very much for your solutions and response.

Regards,
GAFUR,
Covansys.

GAFUR · New User Joined: 19 May 2005 Posts: 31

Hi DavidatK,

Thanks for your response.

Regards,
GAFUR,
Covansys.

manjinder · New User Joined: 04 Dec 2005 Posts: 45 Location: pune

hi gafur
frnd you can read last read one alternate method is to use the temporary variable move the records to tht variable and at the EOF display the temporary variable it will display last record.

perform read-para until EOF
display temp.
read-para.
read file until EOF='Y'.
if not EOF then
move low values to temp.
move inrec to temp.

try this one
correct me if wrong

manjinder · New User Joined: 04 Dec 2005 Posts: 45 Location: pune

hi gafur
frnd you can read last read one alternate method is to use the temporary variable move the records to tht variable and at the EOF display the temporary variable it will display last record.

perform read-para until EOF
display temp.
read-para.
read file until EOF='Y'.
if not EOF then
move low values to temp.
move inrec to temp.

try this one
correct me if wrong