RE: RPG - conversion vs re-write -- MIDRANGE-L

John,

Yeah, this is a good idea. I've done that. I have the old 0001/01/01 or 
similar as a named constant, and I also insert the DFT(0001/01/01) keyword 
in the DDS for new applications so that today's date isn't the default. 
(Too bad RPG IV doesn't import this default values, heh John? <g>)

Then you could do
D NULL_DATE        C                          Const(D'0001/01/01')
C            IF    myDate = NULL_DATE
C            /* do my null-date routine here */
C            endif

Caveat, what is it we still can't do /* */ for comments in RPG IV, Hans?


Bob Cozzi
Bob@RPGIV.COM
www.rpgiv.com
AS/400 Books:  http://www.rpgiv.com/as400Books.html


On Wednesday, September 10, 1997 5:43 PM, John Carr 
[SMTP:74711.77@compuserve.com] wrote:
>
>
> RE:   Re: RPG - conversion vs re-write
>
> <snip>
>
> >And John, you still haven't said what inaccurate date we should use to
> >signify a date field that is unfilled yet.
> <snip>
>
> Do the dates the same way you're doing them now.   00/00/00 means 
something
> unique in your code, right?   Like  ( XXXDATE  IFEQ  0 ) or something 
like
> that.   Have a "Default" date in your D-Spec initialized to 0001-01-01 
and
> heck call it ZERO_DATE if you want to.  Then change the code to say
> (XXXDATE IFEQ   ZERO_DATE)  It means the same to your logic.
>
> Unless you use the CHANGE keyword in DDS (which still might have 
problems)
> in your code right now you don't know if the user keyed in a zero date
> on the display file entry field or she/he just left it blank(Zero - means
> a real null response?).
>
> The real problem is,  what does zero (00/00/00) mean to your 
applications?
> Is it an un-initialized field?  How does it get into the data base file
> to begin with?  Display file entry screen?  If that is the case just
> transmutate it from screen to data base file.   If the user enters a
> 00/00/00 convert that to a 0001-01-01 in your data base file.
>
> It will be just as easy to sort, select/omit, extract, etc.
>
> Check where you really use the 00/00/00 and see what your REALLY trying
> to mean/denote in that instance.
>
> Sometimes when we first write out a record we may not know all the
> information.  In alot of Customer Order files if you don't know the
> expected ship date, or actual ship date, or expected completion date,
> or actual completion date, or , or , or.  What do you put in those fields
> now and why?   Zero's aren't really correct are they?  Neither are
> 99/99/99 what does that suppose to mean?   Maybe Nulls for the
> "Actual" dates but for the "Expected" dates?
>
> Come to an agreement with your users the same way you did when the
> system started and say;
>
> "Hey everybody, when you see a 00/00/00 in actual ship date, it means we
>  don't know. Now you will see a 0001-01-01, it means we still don't know.
>
> A rose is a rose.
>
> Find the meaning of the "Figurative Constant" 00/00/00 or 99/99/99
> and make a new representation for that meaning to your users.
> (Like 0001-01-01 or 9999-12-31)
>
>
> John Carr  CDP
> EdgeTech
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