Re: Re: Do we really need NULL??

Hi,

Maybe I've got the wrong end of the thread regarding NULL, however, I belive that NULL is used to represent NOTHING, NULL should not imply MISSING or UNKNOWN or NOT-APPLICABLE directly.

I would suggest that you use an attribute facet so that you can identify why a particular attribute has been designated NULL.

On the other hand you can insert your NULL extensions directly into attributes, for example

	N/A	for Not applicable
	U/R	for Unreadable
	V/M	for Missing value

Martyn Jones
Compaq Information Management HQ
Munich, Germany

>I work for an organisation that stores medical and survey data. For us
>it is not enough to have simply NULL for missing data - we need to know
>whether
>
>* value was not applicable for this person or
>* value was unreadable on the form for this person or
>* value was missing on the form for this person.
>(and perhaps other varieties of "NULL" in the future)
>
  Received on Tue Nov 15 1994 - 16:29:31 CET