RE: BIGINT Field Size -- RPG400-L

Hans,

I agree that (look back) it would have been a good idea to create 1i0
2i0 4i0 and 8i0, however since today we are required to code 10i0 for a
4-byte int, why not add support for the "more clear" declarations? Why
not allow use to migrate towards  1i0 2i0 4i0 and 8i0?  That way when
you add 16i0 it will be all the better.

Bob Cozzi
www.rpgiv.com/seminars



-----Original Message-----
From: rpg400-l-admin@midrange.com [mailto:rpg400-l-admin@midrange.com]
On Behalf Of Hans Boldt
Sent: Wednesday, September 04, 2002 8:36 AM
To: rpg400-l@midrange.com
Subject: Re: BIGINT Field Size


bill.reger=lADxs7XRq0eakBO8gow8eQ@public.gmane.org wrote:
> Just out of curiosity, does anyone know why 8-byte Integer fields
> (type
> BIGINT) are required to be defined as length 20 when the highest and
lowest
> allowed values are only 19 digits?  The allowed range of values is
> documented to be from -9,223,372,036,854,775,808 to
> 9,223,372,036,854,775,807 (19 digits in each case).
>
> All the other Integer data types require lengths that equal their
> range of allowed values.  For example SMALLINT fields have a range
> from -32,768 to 32,767.  All valid integer field definitions are shown

> below:
>
> D TinyInt         S              3I 0
> D SmallInt        S              5I 0
> D Integer         S             10I 0
> D BigInt          S             20I 0
>
> Like I said, I'm just curious.
>
> Bill

A simple design decision.  Back when we added 2 and 4 byte integer and
unsigned variables, we had to decide between defining the variable in
terms of bytes (that is, 2I, 4I, 2U, & 4U) or in terms of digits (5I0,
10I0, 5U0, & 10U0).  There were advantages and disadvantages to both
approaches, and in the end, we decided on number of digits for
consistency with the decimal numeric formats.

The next release, we added float, and number of digits really didn't
make sense there, thus 4F and 8F.  In retrospect, if we realized that at
the time we added integer and unsigned, that may have tipped the scales
towards 2I, 4I, etc.

That brings us to the 1 and 8 bytes integer and unsigned numerics. An 8
byte unsigned can hold a 20 digit value, but unfortunately, an 8 byte
integer only goes up to 19 digits.  To be consistent, we defined both
the 8 byte unsigned and the 8 byte integer as 20 digits.

You might then ask, what if we ever went to 16 byte integer and
unsigned?  Fortunately, integer and unsigned are consistent.  But
unfortunately, it's an odd number of digits - 39.  Would we define those
formats as 39I0 and 39U0?  Or would we use 40I0 and 40U0?  Who knows?
Fortunately, we don't foresee a need to make that particular design
decision any time soon.

Oh BTW, talking of numerics, in V5R2 we increased the maximum size of a
packed decimal variable to a whopping 31 digits!

Cheers!  Hans



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