Re: L-date fields

[Glenn Ericson <Glenn-Ericson@xxxxxxx>]

At 03:15 AM 9/16/97 +0000, you wrote:
>lgoodbar@tecinfo.com wrote:
>
>>For birthdates, the system will only accept the current or previous
>>century. If today is 1997/09/15, and the user enters 091597, the
>>system will "assume" 1997; however, if the user enters 091697, the
>>computer "assumes" the previous century because the date is "after"
>>today.
>
>This logic is faulty. In the early years of the next century there will
>still be people alive who were born in the 19th century. You can't just
>default to the previous century if you're covering a period that spans
>more than a hundred years. Assume the current year is 2001. Based on a
>maximum human life span of 120 years the range of valid birth years
>(sliding window) will be 1881 - 2001. The user enters a DOB with a 2
>digit year of 52. It's a reasonable assumption that this is 1952 and
>there is no need to force the user to enter 4 digits for the year. The
>user enters a birth year of 97. This could be the DOB of a 4 year old
>born in 1997 or a 104 year old born in 1887. Assuming our database can
>encompass both these people (again, know your data) the program must now
>either force the user to enter the century or guess the century and
>force the user to confirm or reject the guess.
>
>Similarly, if the current year is 2050 and the user enters a birth year
>of 46, it's not safe to assume that this year is "in the past" therefore
>it must mean 2046. It could just as well mean 1946.
>
>Dave Kahn - TCO, Tengiz, Kazakstan
>=========
>
>e-mail:  kahn@tengizchevroil.com    (until September 30th)
>         dkahn@cix.compulink.co.uk  (from  October 1st)
>
>+---
David 
interesting you spanned  two centuries in your example.  OS/400 has not
facility in it's fixed windowing techniques to handle any dates before
1900. [ 0 is 19xx and 1 is 20xx].   I don't care for -1 for 18xx.

 Another thought is  what happens to the 19xx dates between 1900 and 1939?
Do they  default to 20xx?

Glenn
___________________________________________________
Glenn Ericson,          Phoenix Consulting                      
P O Box 701164   East Elmhurst NY 11370-3164 USA                            
Ph. 718 898 9805         Fx. 718 446 1150
AS/400 & Year 2000- - Solutions Specialists
 © 1997copyright,  all rights reserved
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