Automatic vs. demand indexes

[GCC Consulting]

> -----Original Message-----
> From: 
> filepro-list-bounces+gccconsulting=comcast.net at lists.celestial
> .com 
> [mailto:filepro-list-bounces+gccconsulting=comcast.net at lists.c
> elestial.com] On Behalf Of fp at casabellagallery.com
> Sent: Wednesday, July 11, 2007 2:03 PM
> To: Nancy Palmquist
> Cc: filePro List
> Subject: RE: Automatic vs. demand indexes
> 
> Nancy posted:
> 
> [...]
> > 
> > However, I had cause to try the exact same thing with a 
> Demand index. 
> > Built on the same two fields: state & city Built with the same two 
> > lengths: 2 & 8
> > 
> [...]
> 
> I always thought demand indexes were really meant to be used 
> for reports not browse.  Truth is that I have never used them.
> 
> I do have a couple of questions for you:
> 
> Q. Don't demand indexes need to be rebuilt every time you
>    invoke them?  If not rebuilt, don't they have only data
>    as per last built?
> 
> Q. If they do need to be rebuilt, do they actually rebuilt
>    faster than using 'drop' within your code?
> 
> It never occurred to me you could use demand indexes this way 
> mainly because of my stated understanding (them having to be rebuilt).
> 
> Regards,
> 
> 
> Jose Lerebours

Jose,

I have a number of programs that use demand indexes with browses.

Some are older apps in which the brose is to master files that do not change
often.

To get around the problem of rebuilding when adding new records, I created a
separate add record menu option which when exited, rebuild the demand
index(s) involved.

A new application that uses demand indexes is a call center program allowing
my client the ability to create specific sets of data to be used.

Although using demand indexes, for security reasons, drops are used even
here to insure that only data with the primary key is displayed.  

With the speed of the computers today, rebuilding even very large indexes is
fairly quick.  Drop when used on a large file can have delays in displaying
data and at time appear "draggy" when scrolling through a list.

Richard Kreiss
GCC Consulting