Maybe try something like this:
- Set an error handler
- Try to use that field or variable
- If it is null then the error handler will catch it
eg:
ON ERR CALL("errorcatcher")
$result:=$BooleanVarOrfield=true
ON ERR CALL("")
On 2 June 2018 at 15:02, Arnaud de Montard via 4D_Tech <[email protected]
> wrote:
>
> > Le 1 juin 2018 à 20:39, Chip Scheide via 4D_Tech <[email protected]>
> a écrit :
> >
> > I meant - I was looking for a command which behaved like Nil(), but for
> > Null.
>
> Hi Chip,
> I had a bad recent experience with a legacy db in which check box "convert
> Null to empty" was sometimes on, sometimes off… The use of QUERY command,
> in that situation, is risky:
> //example with date
> QUERY($table_p->;$field_p->=!00/00/0000!)
> $empty_l:= Records in selection($table_p->)
> QUERY($table_p->;$field_p->#!00/00/0000!)
> $notEmpty_l:= Records in selection($table_p->)
> ASSERT(Records in table($table_p->)=($empty_l+$notEmpty_l);"data
> integrity or bad Null setting")
>
> It's checked everywhere now.
>
> In a brand new DB, and *knowing what strategy has been adopted about Null
> use*, things could be different.
>
> --
> Arnaud de Montard
>
>
>
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