Re: Null value into an integer variable

[Rolf-Werner Eilert <rwe-sse@xxxxxxxxxx>]

Am 19.04.24 um 11:20 schrieb BB:
> On 19/4/24 6:25 pm, Mayost Sharon wrote:
>
> > Hello
> >
> >
> > Public Sub Main()
> >    Dim sVar As String
> >    Dim iVar As Integer
> >
> >    sVar = "gb"
> >    iVar = 3
> >    sVar = Null
> >    iVar = Null
> > End
> >
> >
> > When I put an Null value into a variable of type string I don't get an 
> > error and the variable gets a value of ""
> >
> > But when I put an Null value into a variable of integer type it gives 
> > an error
> >
> > Is this normal?
> >
> > Thank you
> Very much so! A string of zero length is considered a null or vice versa 
> a null is considered a string of zero length. But consider the internal 
> (memory) representation of an integer. There is no way to represent a 
> null value.
>
> This is of course a big PIA when dealing with databases where integer 
> columns can contain nulls and that has a very specific meaning i.e. "no 
> value has been set". I have to date, after some time considering this, 
> have not arrived at a viable solution.
>
> Why do you want to set an integer variable to Null?
>
> b

Usually I try to catch this case by checking for "" and IsNull(Val(...)) 
like

If sMyString = "" Then
  iMyInteger = 0
Else
  If IsNull(Val(sOriginal)) Then
    iMyInteger = 0
  Else
    iMyInteger = Val(sOriginal)
  End If
End If

to be completely sure.

Regards
Rolf