B-Tree Index Usage

Hi
Since I hope that Raining Data will be doing a significant amount of work on
D3 Indices in the not too distant future - Tdata and Mark Brown have
confirmed my results and requests are now being prepared - I would
appreciate your opinions on how to form or perhaps dump my request.

I have been very surprised at the number of people who have indicated
verbally or through cdp that translates to index across two files are a bad
idea. To my mind this indicates a problem with the implementation methods
not the design. The procedure is not rocket science.
For example a file (I can't call it a master file according to DAWN :-) )
contains the name and another file contains multiple addresses.
On creation of an address we write an index Name:Address key
On alteration of a name we loop through, delete the old Name:Address key and
create the new one. Note that this sort of thing is even rarer these days
than it was 20 years ago as many girls retain their own account names on
marriage these days, so it is not a big load.

What is missing in the D3 scenario is a re-index(filename,oldkey,newkey)
that can be used from basic or a trigger. In fact it almost sounds like the
defunct b-correlative but that was purely to get round the problem of trying
to write programs using/abusing an editor instead of the proper programming
language - imagine trying to write programs with VI as the driver.

By the way my latest testing indicates that a Sort will not use a date index
unless there is a limitation on it.
SORT FILE BY DATEINDEXADI will not use the index according to the result
message
SORT FILE BY DATEINDEXADI NE "1-4-2006" will use the index.
To make life even more interesting there is a difference in date
interpretation betwwen ACCESS and a program. If one forgets to SET-DATE-EUR
to get the proper format the program DM,BP, DATE will still give one the
correct format as per the setting on your winbox whereas ACCESS will try and
use the US format. This can lead to a little head scratching for a minute
or two.

Peter McMurray


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