Linda
Since R:Base 3.0, I have been advising people that the most thorough way to
check for not equals as well as NULL is by writing the code this way:
SET VAR v1 TEXT = NULL
SET VAR v3 TEXT = 'test value'
IF v1 <> v3 OR (v1 IS NULL AND v3 IS NOT NULL) THEN
You must test for BOTH. R:Base is doing it RIGHT. I'd suggest fixing your
code and then reinstalling 6.5++ - it's WELL worth it!
David Blocker
----- Original Message -----
From: "FISHER" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Wednesday, June 27, 2001 5:10 PM
Subject: Null Warning - 6.5++ for Dos Upgrade
> We just installed the latest upgrade this morning and had to uninstall
> shortly thereafter in order to modify our code to account for the
> correct handling of Null value comparisons.
>
> I had read the Bug Fixes and Enhancements at the time of the install
> but didn't think that the change in how R:BASE was evaluating NULL
> values would affect us since we were using the OFF EQNULL setting and I
> knew that we rarely compared two null values. However, a change related
> to the results of comparisons of null values to text values when EQNULL
> is OFF wreaked havoc with our program flow. Below I have outlined the
> results of comparisons of null values to text values by R:BASE in 6.1,
> 6.5+ 6.5++ prerelease and 6.5++.
>
> SET VAR v1 TEXT = NULL
> SET VAR v3 TEXT = 'test value'
>
> Version 6.5++ 6.5++ 6.5 + 6.1
> Build 1.842 1.840 1.839
> 6.1ax
> IF v1 <> v3 THEN False False True True
> IF v1 NE v3 THEN False True True True
>
> As far as I can tell, and I have done extensive evaluations with
> INTEGER and DATE variables including BETWEEN and NOT BETWEEN checking,
> the only change that occurred when EQNULL is set to OFF is with the
> comparison of TEXT values as outlined above. Also, the reason we didn't
> identify this when with the beta's is because we routinely use the NE
> syntax instead of <>. Hopefully this will allow some of you out there
> to plan for the upgrade better than we did.
>
> Linda Fisher
> Manager, Data Services
> CIMRO Quality Healthcare Solutions
> 208 Metro Dr.
> Jefferson City, MO 65109
>
