On Wed, 18 Jul 2001 09:33:47 EDT [EMAIL PROTECTED] wrote:
> OK, I KNOW when I hear the answer to this, I'm gonna have a headache from
> slapping myself in the forehead, and yelling "Duuuhhhhhhh" <g> but I HAVE to
> ask.
you are in good company :-) i teach programming and each language
has different rules about the status of variables.
in a conventional programming language DEFINING a variable, e.g.
integer fred
doesn't have to give it an initial value. some langauges
in the above case give fred an initial value of zero.
some languages use the status of undefined, null is often used
when looking at pointer variables. the ieee arithmetic standard
allows NaN - not a number to allow for operations that yield
an inappropriate result.
relational algebra and sql have a specific meaning for null, meaning
missing value.
>
> When you define a variable, isn't it already a null value?????
> And if I want to explicitly set a variable to null, do I use:
>
> Set Var vName = null
>
> or
>
> Set null -0-
> set var vName = -0-
>
> ( I KNEW I shouldn't have slept in that part of the class <g>)
> TIA.
>
> Damon
>
> Damon D. Kaufman
> President
> Stalder Spring Works, Inc
> ISO-9002 / QS-9000 Certified
> 2345 S. Yellow Springs St.
> Springfield, Ohio 45506
> Voice 937.322.6120
> Fax 937.322.2126
> email: [EMAIL PROTECTED]
>
> In a message dated 7/17/2001 8:01:14 PM Eastern Daylight Time,
> [EMAIL PROTECTED] writes:
>
> << >... your I/O issue may explain some "bugs" that I
> >have encountered as well. I think I'll adopt a similar
> >policy and switch to inserting only constant values
> >and not expressions ...
>
> William,
>
> 01. Make sure that the data type of variables used in
> expressions matches with the data type of column.
>
> 02. Always pre-define those variables as NULL
> >>
--
Ian
[EMAIL PROTECTED]
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