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Adding New fields to Copybook and Impacts?


IBM Mainframe Forums -> COBOL Programming
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ykishore

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Joined: 12 Aug 2005
Posts: 53
Location: USA

PostPosted: Wed Jan 18, 2006 12:02 pm
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Hi All

Here is my requirement...

I have a copybook of length 100 bytes. I want to add 4 new fields and i dont have any reserve place in that copybook. then , im planing to convert all numeric fields to COMP-3 ,from that i can get some extra space and i can declare 4 new fields. and i want to know like are there any impacts due to this conversion? can you please let me know all possibilities.....
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ykishore

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Joined: 12 Aug 2005
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PostPosted: Wed Jan 18, 2006 2:36 pm
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HI All

Please do respond to this.....since itz an urgent requirement......
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guptae

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Joined: 14 Oct 2005
Posts: 1208
Location: Bangalore,India

PostPosted: Wed Jan 18, 2006 3:00 pm
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Hi,

It will effect .

1)Suppose A program is using it. & In A program there are stmt to move alphanumeric values to those numeric variable which u changed to COMP-3. It will give u error.

2) Performance issue will be there.
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ykishore

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PostPosted: Wed Jan 18, 2006 3:25 pm
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Hi

Thanx for ur reply.......But im sure that , there were no moments to alphanumeric fields. I mean the fields i converted to COMP-3. Any other impacts...??? cc problem is, if i increase the copybook size , itz going to be a huge impact....instead of that, im thinking in this way....plz put ur comments and ideas on this.........that wud be gr8 help.....
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DavidatK

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Joined: 22 Nov 2005
Posts: 700
Location: Troy, Michigan USA

PostPosted: Thu Jan 19, 2006 12:04 am
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Hi ykishore,

I think you are stuck with a huge impact if you change the copybook.

From what I gather you?re considering changing ?PIC 9(5)? to ?PIC 9(5) COMP-3? and save the two bytes, correct? Change many of them and you can gain enough space for your new fields.

This can be done, but you must re-compile every program that uses the copybook, and find every program where someone is using the file with a hard coded file layout because the offset of the old fields in the copybook have now changed. This can be a daunting task.

By making the Zoned Decimal fields COMP-3, there will be a small, probably imperceptible efficiency gain. COBOL converts Zoned Decimal to Packed Decimal for arithmetic operations, and the back to Zoned Decimal to store the result.

If you change the copybook length, still, all programs, and JCL must change due to this.

As an alternative, and only you can tell us the impact of this, is to come up with an AUX file for the new fields, a second file keyed the same as the master with so the files can be kept in sync. This way, the only programs that will be affected by the new fields will be the ones using them. They will have to read the Master and AUX files.

Whatever method you use, be sure to include ample filler in the copybook so this doesn?t happen again.

Happy Copybook changes,
Dave
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ykishore

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PostPosted: Fri Jan 20, 2006 10:29 am
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Hi

Thanks a lot for your info...
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sonasheetal

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Joined: 08 Jun 2005
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PostPosted: Wed Feb 01, 2006 3:09 pm
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Hi ,
Can u tell me in detail how to convert com filed to com-3 in mainframe environment.
give me one e.g

thanks
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