Re: forcing null values into #variables?

["Aultman, Steven (SMAU)" <SMAU@CHEVRON.COM>]

Fair enough.  I stand corrected.  Thanks.

> -----Original Message-----
> From: Charles Thompson [SMTP:THOMPSONC@TRANSPOWER.CO.NZ]
> Sent: Monday, December 14, 1998 4:38 PM
> To:   Multiple recipients of list SQR-USERS
> Subject:      Re: forcing null values into #variables?
> Sensitivity:  Confidential
>
> Steve,
>
> Sorry to stick my nose in here, but I feel I must have my say !
>
> You seem to have run afoul (note nautical reference) of a database design
> trap:
>  Trying to derive multiple meanings from a single field.  Numeric fields
> should
> NEVER allow nulls, in my view (and SQR agrees).  You should use another
> field
> if you wish to convey one or more of the following :
> - The numeric value has not yet been entered
> - The value is not known
> - The value has been cleared/deleted
> - The field is invalid based on other field values
>
> In this case, another Yes/No field should be used to indicate that there
> is no
> information available currently.
>
> - Charles Thompson
>
> >>>Why is a zero unacceptable?  The business I'm supporting is Shipping
> Loss
> >>>Control.  The column in question is a measurement of liquid cargo lost.
> The
> >>>measurement may not have been taken, in which case a NULL is the
> correct
> >>>answer (no information available).  If the measurement was taken and
> zero is
> >>>the answer, we had a very good voyage (no cargo lost).  I can't use
> zeroes,
> >>>or any other number, to represent the lack of a measurement.  Sybase
> >>>understands the distinction and allows resetting numeric columns to
> NULL in
> >>>ISQL.  Why shouldn't it be possible in SQR?  I'm trying to retain the
> >>>numeric attributes (so I can do more math with the number) for when I
> do
> >>>have a measurement.
> >>>
> >>>Thanks,
> >>>Steve
> >>>> -----Original Message-----
> >>>> From: Wanko, Christopher G, CFCTR [SMTP:apollo@att.com]
> >>>> Sent: Monday, December 14, 1998 11:44 AM
> >>>> To:   'SMAU@CHEVRON.COM'
> >>>> Subject:      RE: forcing null values into #variables?
> >>>>
> >>>> > Is there a way to force a null value into a #variable?  I
> >>>>
> >>>        (SNIP)
> >>>
> >>>> You may different responses, but perhaps you might explain why a zero
> is
> >>>> an
> >>>> unacceptable result to you.
>  >>>>
> >>>        (SNIP)
> >>>
> >>>> -Chris
> >>>>
> >>>>