Re: [Hsqldb-user] Strange behavior comparing to null

[Jim E. <jim...@be...>]

I'm using 1.7. I wasn't sure if 1.7.2 was stable/production (and 
changing the database version requires a major regression test of our 
entire application, which we can't do at this stage in our release 
process). For now I've fixed this issue with a workaround in Java, but 
I'd certainly appreciate learning more about this property setting, or 
that the behavior is different in newer releases of Hypersonic.

	-Jim

On Jul 30, 2004, at 18:26, Andrew Chandler wrote:

> Which version are you using?  I thought this stopped even working at 
> all
> under 1.7.2 - if not I'm almost positive there is a property file 
> setting
> for the database that disabled it but could be wrong.
>
>
>> -----Original Message-----
>> From: hsq...@li...
>> [mailto:hsq...@li...] On Behalf Of
>> Jim Elliott
>> Sent: Friday, July 30, 2004 2:58 PM
>> To: hsq...@li...
>> Subject: [Hsqldb-user] Strange behavior comparing to null
>>
>> I was trying to track down a bug in our application that was
>> reporting links to a new record in the process of being
>> created, and discovered it was being caused by a join that
>> was comparing a column to null. I would expect any such
>> comparison to always fail, but if the column value was null,
>> that row was being returned.
>>
>> I searched the mailing list and found a recent posting,
>> <http://sourceforge.net/mailarchive/message.php?msg_id=8562992>,
>> which describes this as a feature, albeit a "non-standard and
>> deprecated" one. Indeed, it is so non-standard that I had to
>> write some special case code in Java to avoid the problem.
>>
>> Is there any way to turn this "feature" off?
>>
>> Here's the text from the posting to which I am referring:
>>
>>
>>> From: fredt <fredt@us...>
>>>  Re: null = null BUG?
>>> 2004-05-28 07:41
>>>  In the first query, the engine interprets "select 1 from
>> dual where
>>> null =  null" as WHERE NULL IS NULL. Note that you have
>> used NULL as a
>>> literal. The  use of "something = null" is non-standard and
>>> deprecated. You should use  "something is null" instead.
>>
>> Unfortunately, by the time the query gets generated and hits
>> the database, it is indeed comparing a literal NULL to a
>> column. It would be much better if even in this case, the
>> normal semantics of "anything compared with NULL is false" applied.
>>
>> Is this possible?
>> --
>> Jim Elliott
>> Berbee
>> 5520 Research Park Drive Madison, WI 53711
>>
>>
>>
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