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What is difference between Overrides and symbolic parameters

PostPosted: Mon Oct 18, 2010 9:34 pm
by Vamsi Krishna Nalla
Can anyone explain?

Re: What is difference between Overrides and symbolic parameters

PostPosted: Mon Oct 18, 2010 9:48 pm
by MrSpock
Is your question related to JCL or to using JCL procedures?

JCL Procedure Modifications are documented here if that's what you're looking for.

Re: What is difference between Overrides and symbolic parameters

PostPosted: Tue Oct 19, 2010 12:25 am
by Bill Dennis
Both methods have their advantages. Some JCL values and parameters can be modified either as symbolics or overrides. A few can only be changed using one of the two methods.

An example is PGM= on an execute statement. You can make program name a symbolic but it cannot be overridden in a procedure.
//MY        PROC PROG=BAL1    default value
//STEP1     EXEC PGM=&PROG    <== acceptable
//   PEND
//RUN    EXEC  MY,PROG=THIS1     symbolic
.
//MY        PROC
//STEP1     EXEC PGM=BAL1
//    PEND   
//RUN    EXEC  MY,PGM.STEP1=THIS1  <= unacceptable

Re: What is difference between Overrides and symbolic parameters

PostPosted: Wed Oct 20, 2010 12:02 am
by Ferrari2010
Hi,

Overrides
1. Used to replace existing file with another file
Ex: You are using file infile1 as input in your job and want to use another file infile2 instead of infile1, you can override the infile1 with infile2 in the jcl to pick the infile2 instead of infile1.
Please check the syntax for file override.
2. you can use to dummy the infile.
Ex: if you don't want to process the input file, but still want to run the job successfully, you can override the input file with DUMMY.

Symbolic parameters
1. This is very powerful practice when you update the big jcl's. If in one jcl you are using many files and all the files share the same qualifier, using symbolic parameters you need to give only at once that particular qualifier. if you want to change the qualifier, you need to change only at one place.

There are some other differences and benfits also.
Both playes very important role in JCL.

Thanks,

Re: What is difference between Overrides and symbolic parameters

PostPosted: Mon Oct 25, 2010 12:50 pm
by Manikavasan
Symbolic & Override parameters:
----------------------------------------

Please find the example below.hope it will be clear.

JCL for executing proc:
----------------------------
//MC24447  JOB (124E),'MANIK' ,CLASS=A,MSGCLASS = 0,
//                      MSGLEVEL=(1,1),NOTIFY=&SYSUID
//PROCLIB  JCLLIB ORDER=(MMAT.TEST.PROCLIB)
//               INLCUDE MEMBER = JOBLIBJ
//PROC1     EXEC TESTPROC
//               LIBPFX=MMAP          -----> SUBSTITUTION PARAMETERS
//               DSNPFX=MMAP
//               PROD=PROD
//               SOUT=*

(OR)

//MC24447  JOB (124E),'MANIK' ,CLASS=A,MSGCLASS = 0,
//                      MSGLEVEL=(1,1),NOTIFY=&SYSUID
//PROCLIB  JCLLIB ORDER=(MMAT.TEST.PROCLIB)
//               INLCUDE MEMBER = JOBLIBJ
//PROC1     EXEC TESTPROC
//TESTPROC.INFILE DD DSN=MMAT.TEST.FILE1,DISP=SHR --->OVERRIDE PARAMETERS
//


PROC:
--------
Proc given below is catalog procedure.
LIBPFX= library prefix
DSNPFX = Dataset Prefix
//PROC1     TESTPROC               
//          LIBPFX=MMAP          -----> SYMBOLIC PARAMETERS
//          DSNPFX=MMAP
//          PROD=PROD
//          SOUT=*
//STEP1     EXEC     PGM=TESTPGM
//INFILE     DD        DSN=&DSNPFX..&PROD..INPUTFILE,DISP=SHR
//OUTFILE  DD        DSN=&DSNPFX..&PROD..OUTFILE,     
//                         DISP=(,CATLG,CATLG),                             
//                         SPACE=(CYL,(1,1),RLSE)
//SYSIN      DD        DUMMY
//SYSOUT   DD        SYSOUT=&SOUT
//SYSPRINT DD        SYSOUT=&SOUT
//

Entries "Code'd" and corrected but not aligned completely.

Re: What is difference between Overrides and symbolic parameters

PostPosted: Mon Oct 25, 2010 5:39 pm
by NicC
Manakavisan,

First, read the forum rules - you will see that they say you should use the code tags when posting code - this keeps the code aligned properly making it easier to read.
Second, you have JCL errors in your posted code - you are missing commas, have spaces either side of an = character and your override is wrong: it should be
//STEP1.INFILE DD ......

Re: What is difference between Overrides and symbolic parameters

PostPosted: Tue Oct 26, 2010 11:03 am
by Manikavasan
ok will follow it