Big Flat Stacks - NULLs

Paul Looney support at
Wed Jun 16 23:27:49 EDT 2010

Thanks for the excellent explanation.
So far we have imported over a thousand HC stacks into our Rev-based  
business system. These are mostly databases from our customers.
We noticed that, with some customers, up to a third of the archived  
orders did not make it into the new system. When checking further, we  
found these were customers who regularly pasted text from MS Word or  
AppleWorks into one of the Notes fields. Incidentally, removing the  
NULLs before import was not always successful, either.
Another NULL problem in Rev has been sorts. We've found that  
information is often missing when sorting data containing NULLs (on  
one occasion, the pre-sort data was two megabytes larger than the  
post-sort). Removing NULLS from the data before sorting (which we  
always do now) has fixed the problem for us.
Paul Looney

On 16/06/2010, at 7:21 PM, J. Landman Gay wrote:

> Bob Sneidar wrote:
>> I vaguely recall that HC was not supposed to have nulls, but some bug
>> or other caused them and wrecked havoc with HC stacks. Compacting the
>> stack seemed to eliminate them.
> HC used nulls as end-of-field markers, so if text containing nulls  
> was pasted into an HC field, the text would truncate at the first  
> null. I once had to debug a stack like that, where someone had  
> pasted some text from AppleWorks into the stack. It wasn't a bug,  
> just a result of pasting.
> Rev handles nulls in fields fine. But during a normal Rev import,  
> the Rev engine knows that nulls were end-of-field markers in HC and  
> so probably truncates the incoming text at that point too, just as  
> HC did.
> I'm not sure why Paul would need to replace incoming nulls with  
> empty though, since the Rev engine shouldn't bring any of them in  
> when it opens a HC stack.
> -- 
> Jacqueline Landman Gay         |     jacque at
> HyperActive Software           |
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