field length change



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field length change

Postby mahesh77 » Mon Jul 06, 2009 12:13 am

Hi,

I Know its not that easy to change field lenght in a record, but jus assume u got a client request and u have to change it, we can manage if its cust name, cust loc, or cust address by using filler fields, but what if get a change request asking to change accnt num which is numeric.........is it possible? if so then what are the other things that get changed also...............
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Re: field length change

 

Re: field length change

Postby dick scherrer » Mon Jul 06, 2009 2:40 am

Hello,

There must be something i am missing. . .

There is little difference in changing a name versus changing an amount.

Every single reference to the field must be identified (known as impact analysis) and modified for the new definition. This would include every file definition, every screen, every report, everywhere it is used in working data or a parm, etc. One or more conversion routines may be needed to reformat the existing data to the new format - this would include backups or other copies that may be needed later.

Why do you believe it is different when changing the length of an amount?
Hope this helps,
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Re: field length change

Postby Anuj Dhawan » Mon Jul 06, 2009 1:04 pm

we can manage if its cust name, cust loc, or cust address by using filler fields
What if the length of cust name, cust loc, or cust address is also changed and go out of FILLER capacity? How do you manage that today?
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Re: field length change

Postby mahesh77 » Tue Jul 07, 2009 1:00 pm

hey anuj

then we need a conversion program which reads the old format and writes new format.........
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Re: field length change

Postby dick scherrer » Wed Jul 08, 2009 12:03 am

Hello,

Why would changing some numeric field be any different. . .?
Hope this helps,
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Re: field length change

Postby mahesh77 » Wed Jul 08, 2009 12:13 pm

hey dick,

change numeric fields is difficult, moreover changing account num is much more difficult,account num in index sequential file ,ksds file serves as index,generally they create account number to identify u separately when it stored on computer,

If the account number is numeric, you can convert it to Packed Decimal (Comp-3) for an increase to 11 digits. If the account number consists of letters and digits, you can use a simple compression algorithm to store 8 characters in 6 bytes.
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Re: field length change

Postby dick scherrer » Thu Jul 09, 2009 12:20 am

Hello,

No, changing a numeric field is not more difficult - someone might make it more difficult, bue it does not need to be any more difficult than changing the length of a "name".

moreover changing account num is much more difficult,account num in index sequential file ,ksds file serves as index,generally they create account number to identify u separately when it stored on computer,
Yes, because of the impact of the change, not because it is numeric.

If not only the length of an item changes, but the business rules regarding it change, that will surely be more "difficult" as it will probably have a greater impact.
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Re: field length change

Postby BChat » Thu Jul 09, 2009 9:33 pm

Mahesh,
Your "accnt num" was just a numeric field in the beginning;
then it also became an index to a KSDS file;
and finally you said "If the account number consists of letters and digits, you can use a simple compression algorithm to store 8 characters in 6 bytes."

Just wondering what "simple compression algorithm" you have in mind, if it had letters and digits?

Can you please explain your requirement a bit more clearly. Being vague is not being smart...

Thanks
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Re: field length change

Postby mahesh77 » Thu Jul 09, 2009 11:05 pm

hey bchat,

i jus took one topic called " field change" and trying to look at it in different angles, jus lookin what possible ways we have for field change, jus sharing my thought or rather my doubt..........u asked me what r my requirements, jus think as many ways u can use for field changes for all kinds of files
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Re: field length change

Postby dick scherrer » Fri Jul 10, 2009 2:36 am

Hello,

jus lookin what possible ways we have for field change, jus sharing my thought or rather my doubt..........
This could be an entertaining topic to philosophize over - if everyone was sitting in the same place with an "adult beverage". . .

For practical consideration, there is pretty much 4 things one can do with a field - add it to the file, remove it from the file, make it larger/smaller, or change the type.

The true IT professionals do not seek out ways to make things more complicated, but rather more simple. There are few rewards for implementing the most clever solution that others do not understand and cannot maintain.

FWIW
Hope this helps,
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