NULL VarCharString (was Slow NOT searches)

[Ruslan Zasukhin]

On 12/29/05 5:12 AM, "jda" <jda at his.com> wrote:

>> Advantage of making a VarChar field nullable is that you would be able to
>> distinguish between when a field legitimately contains an empty string,
>> either by default or explicit assignment, and when it contains no string at
>> all because none has been supplied for it.  You could achieve the same
>> result by choosing some arbitrary string of your choice to signify "no
>> string supplied", such as "NULL" for example.

right
 
>> Disadvantages are more storage required for storing the per-record isNull
>> information, and slower execution because the nullable information needs to
>> be taken into consideration for many operations you may perform on the
>> field.

One BIT is added per record

 
>> That make sense?
>> 
>> --Ed
>> 
> 
> It would, Ed. But I tested this after posting, and searching for
> WHERE varCharField IS NULL got nothing (all fields had been created
> after SetBlank). Whereas searching for WHERE varCharField IS NOT NULL
> returned all. So I'm thinking that Valentina ignores Nullable for
> varCharFields. Is that right, Ruslan?

Not right.

You need check your data again.


-- 
Best regards,

Ruslan Zasukhin
VP Engineering and New Technology
Paradigma Software, Inc

Valentina - Joining Worlds of Information
http://www.paradigmasoft.com

[I feel the need: the need for speed]