I make extensive use of dbase files for storing local data before transfers
with Server. The reasoning is my software is running in a manufacturing
environment and must keep running even if the lan goes down.
I have found that to successful share the dbase tables across the lan using
the bde the local app MUST use a full unc to access the tables as the same
as the remote apps. This is with dbase files! If you don't what happens is
that when remote app appends data the local app does not see the data that
has been appended or changed and will overwrite it. The down side of using a
full unc for accessing the tables is one of performance, it suffers
dramatically and behaves if it was on a remote machine rather than local.
Also if you use a dbase table watch out for someone using MS Access/VB to
read or update the tables as it will cause problems with data and indexes.
After they have been updated via MS Access/VB you will need to rebuild the
indexes from within your delphi app.
There are also problems with the BDE in using dbase win format (level 5
think). You can create the tables but you can not restructure them, cannot
open them in MS Access/VB, use level 4 or lower.
Paradox is good if you app is bullet proof. If there is an unhandled
exception at the wrong time it will destroy the indexes and occasionally
append junk to the end of the data table as it flushes the buffers and shuts
down.
With Paradox and DBase after you have posted your data flush the buffers.
This ensures that every app sees the same copy of the data. Took a me long
time to work this one out.
One advantage of dbase is if someone turns the machine off while your are
updating tables is the tables will be intact and at the most you will lose
the last few records being appended, and have to reindex.
Always have an option to reindex on the menu or do it automatically at
startup.
That all I can think of just quickly - maurice
-----Original Message-----
From: Steve Peacocke [mailto:[EMAIL PROTECTED]]
Sent: Wednesday, 28 April 1999 19:42
To: Multiple recipients of list database
Subject: [DUG-DB]: LAN - Paradox/Foxpro
I'm interested in you opinions/facts regarding an issue I was recently made
aware of. I am currently writing a LAN based program (client server is NOT
AN OPTION) and have, by default started using Paradox files.
I have been told to look seriously at converting to using FoxPro rather
than paradox files as these have less corruption. Examples are: missing
data; continual index corruption; and data corruption.
I have not experienced any of these but have not loaded up the data as yet,
just enough for the light testing involved in the midst of development.
I realise some data corruption in the fault of not using dbiSaveChanges in
the AfterPost event.
Steve
__________________________________________________________________
|Steve Peacocke ([EMAIL PROTECTED])
| http://trader.co.nz/
| http://trader.co.nz/vizsla/ http://trader.co.nz/vizsla/docking
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