Re: Looking for keyed file package

[Al Christians <achrist@easystreet.com>]

>> It would be interesting to understand why you are 
doing things "by hand" here at such a low level, 
rather than use a DB. <<

The appliction is to use the keyed file to collate 
data from multiple sources.  It's sort of a brief
holding tank for data.  Pick up a file here, a file
there, keep accumulating the information, then 
spit out sequential files for a different 
application to process on a different machine.
The total lifecycle of the application is just a
couple of weeks.  The number of simultaneous users
of the file will probably never exceed 1.  It's not
worth buying a database for, and the speed objectives,
processing hundreds of thousands of records in much 
less than an hour, and the large file sizes make me 
reluctant to try MS Access, the only database likely 
to be available on the target machines.  

All this data is going to come together next month at 
a site that I have not yet visited.  Simpler is better
when preparing to walk into a new location and run
from a cold start.  I don't know if their version of
Access is the same as the one I could use here to 
develop and test, what the differences might
be, or how much trouble they might cause.  I don't want
to find out.  I just need the simplest thing that will
work.  Low-cost doesn't hurt, either.     

I did try each of Pascal Obry's packages and the one 
from Ada-Belgium with no success.  I think that the 
Ada Belgium package has an off by one error that causes
a constraint error when there is an unfortunate 
coincidence of the start of a record with the start of
a block of data in the file.  It would load my data 
and let me access it, but about 1000 records into the
file, it would crash with  a subscript computed as
(something mod 512) being used as an index into an 
array(1..512).   

I'll have to go back and reconstruct my code to re-create
the problems I was getting with Pascal's modules.  That
won't be hard -- he's designed them with a very easy to 
use interface.  Unfortunately, I'm doing this under an
extreme time crunch, so I think I'm going to be going
even more toward the 'do-it-all-by-hand' position using
direct IO.  I'll just create the index in memory each 
time I run by reading the entire file.  Up to a million
records should fit fine. 


Al