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Dynamic file allocation using JCL


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ibmuserj

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Joined: 03 Mar 2022
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PostPosted: Thu Mar 03, 2022 4:18 pm
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Need help. Requirement is to get file name from card input and dynamically allocate in the next step in same JCL. File name contain last month and year as part of name. Possible to perform dynamic file allocation in STEP2? Please advise, Thanks

STEP1: Get last month and year based on run date & append to file name (eg; XXX.TEST.FEB2022). Write the file name to a temporary file

STEP2: Allocate above file. Get file name from card input or temporary file and then allocate

STEP3: Execute program with output written to XXX.TEST.FEB2022
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sergeyken

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Joined: 29 Apr 2008
Posts: 1614

PostPosted: Thu Mar 03, 2022 7:46 pm
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ibmuserj wrote:
Need help. Requirement is to get file name from card input and dynamically allocate in the next step in same JCL. File name contain last month and year as part of name. Possible to perform dynamic file allocation in STEP2? Please advise, Thanks

STEP1: Get last month and year based on run date & append to file name (eg; XXX.TEST.FEB2022). Write the file name to a temporary file

STEP2: Allocate above file. Get file name from card input or temporary file and then allocate

STEP3: Execute program with output written to XXX.TEST.FEB2022


1. All this plan is very similar to the flight from Washington to New York, with transfer on the Moon. There is absolutely no need to store any dataset name (NOT! file name) in any temporary dataset (not FILE!). Otherwise it makes all further operations even more complicated.

2. I do not not think it is extremely critical to use the name of the month, instead of its number, as part of DSNAME, isn't it?

3. What JCL does (as the major part of its functionality) is, allocation and re-allocation of datasets (not files); there is no need to call it "dynamic allocation". There is nothing dynamic in this operation.

Code:
//NEWDSN  DD    DISP=(NEW,CATLG),
//      . . . . . . .
//      DSNAME=XXX.TEST.D&MON&YEAR   
//*   or DSN=XXX.TEST.D&YEAR&MON - for better name list sorting

That's it.
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Garry Carroll

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Joined: 08 May 2006
Posts: 1175
Location: Dublin, Ireland

PostPosted: Thu Mar 03, 2022 9:21 pm
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One possibility would be to generate DFSORT/SYNCSORT SYMNAMES using the input dataset and system symbols. A first step would build the SYMNAMES to be used in the second step. The second step would then dynamically generate the JCL containing the dataset name and, optionally, submit the generated JCL.

Garry.
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ibmuserj

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Joined: 03 Mar 2022
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PostPosted: Fri Mar 04, 2022 8:58 am
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Thanks, will try the options
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Willy Jensen

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Joined: 01 Sep 2015
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PostPosted: Fri Mar 04, 2022 12:47 pm
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A simple REXX or CSECT should do the trick. Could even combine all 3 steps into 1.
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ibmuserj

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PostPosted: Fri Mar 04, 2022 12:52 pm
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trying to achieve via jcl step - not too familiar with REXX
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Rohit Umarjikar

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Joined: 21 Sep 2010
Posts: 2945
Location: NYC,USA

PostPosted: Fri Mar 04, 2022 5:58 pm
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Welcome!
Have you searched before posting ? I am sure similar topic has been discussed several times in past , please use SEARCH option on the top to get closest post and tweak to get it work and that is one of the reason why historical posts are preserved.
E.g ibmmainframes.com/about52338.html
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sergeyken

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Joined: 29 Apr 2008
Posts: 1614

PostPosted: Fri Mar 04, 2022 6:21 pm
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Willy Jensen wrote:
A simple REXX or CSECT should do the trick. Could even combine all 3 steps into 1.

How a CSECT could do the trick, or whatever else, at all?

CSECT stands for "Control Section" - this is a physical part of any object module created by any compiler from any language, when running in zOS environment. One even can't create it manually!
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Willy Jensen

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Joined: 01 Sep 2015
Posts: 628
Location: Denmark

PostPosted: Fri Mar 04, 2022 7:01 pm
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oops, I meant CLIST. Been doing too much assembler lately.
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