Re: null capable fields

[Jim Langston <jlangston@xxxxxxxxxxxxxxxx>]

Just because of that I used to have some subroutines I had written in dBase to
handle
null fields.  If I wanted the value from a field that I knew could be null I
would call a
subroutine something like:

IF GetFieldInteger(MyField, 0) > 10 Then...

GetFieldInteger would have a few ifs, if MyField = Null then return the second
parameter
which was the default (in this case 0) otherwise return MyField.

Otherwise I would of had to code it in all my logic, I found it so much easier 
to
do
in a function.

I haven't' read the manual on RPG IV yet, but program in it, but are there true
functions
now?  So i could say:

EVAL NewVar = GetFieldInteger(MyField, 0)

or

IF GetFieldInteger(MyField, 0) > 10

Regards,

Jim Langston



Joep Beckeringh wrote:

> ----- Oorspronkelijk bericht -----
> Van: McCallion, Martin <MccalliM@Midas-Kapiti.com>
>
>  <snip>
> > Oh.  Thanks.  I thought it must be much more complex than that.
>  <snip>
>
> Oh, but it is, as soon as you get into boolean logic.  Normally, the
> expression 'var > 10' is easily understood.  It is TRUE for all values of
> var greater than 10 and FALSE for 10 and lower.  But what if var is NULL?
> Is the expression TRUE, FALSE or maybe something like UNDEFINED or NULL?
> And if it is FALSE, does that mean that the opposite, 'var <= 10' is TRUE?
> Leads to some interesting IF - THEN - ELSE constructs, especially if you
> combine some expressions.
>
> Joep Beckeringh
>
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