Re: Packed vs. Zoned

[Chris Rehm <javadisciple@xxxxxxxxxxxxx>]

On Tuesday 25 September 2001 08:05 am, Joel Fritz wrote:
> I'll bite.  Before true dates our shop standard for dates was 9 packed
> yyyymmdd.  What are the pros and cons?  Other than having to use a poorly
> documented program for calculating durations and validation, I didn't see
> much of a disadvantage.

Well, I'll toss this in even though it may be just ancient history.

When I was first migrating companies to the AS/400 I ran into a problem with
date fields being stored as packed because the RPG II programs that worked
with the data as flat files wrote differently than the RPG 400 programs which
worked with the data as relational fields.

I had programs getting unexpected results because dates which displayed as
being equal were not (equal) because of different values in the high order
digit's zone.

While this occured with dates, this problem would be the same for any
situation where a numeric field with an even number of digits is stored as
packed. I do not know what the defined behavior is supposed to be for the
treatment of the high order zone when that field is written or read, but I do
know there is a conflict between the way RPG II treats it and RPG 400.


--
Chris Rehm
javadisciple@earthlink.net

And thou shalt love the Lord thy God with all thy heart...
...Thou shalt love thy neighbor as thyself. There is none other
commandment greater than these. Mark 12:30-31