re Text file database, moving from Mac OsX to windows

drphilippegiraudet drphilippegiraudet at wanadoo.fr
Tue Feb 8 02:56:28 CST 2005


Hello

Thanks to Robert Brenstein and Klaus Major for their answers.
The question is not an encoding problem and no more a corruption of 
data because of simultaneous writing access, because I still only 
tested it in mono user access, on windows. I just realise, with what 
Robert says that the corruption by simultaneous writing access will be 
my next problem ;-)))) ... ;-(
the problem is that when you enter a command line such as

write appointment to file Pathway at 
(1001+dayLength*(dayNumber-1)+225+(RoomNum-1)*4001+(AppNum-1)*100-1)

It writes at the rigth place  on Mac

and at the wrong place on windows!

I believe it can't be an error on calculation of the first char: 
(1001+dayLength*(dayNumber-1)+225+(RoomNum-1)*4001+(AppNum-1)*100-1)

I prefer to suppose it is a quetion of length of the chain I write : if 
some chars like return or even tab are not counted , in a 8MB text 
file, it makes a great difference at the end of the file.

but now I have another Question: Robert Brenstein, you wrote me :

"You are not handling file access correctly and the file is getting 
corrupted because more than single person tries to write to it. Setting 
up multi-user access is not so trivial. Using text files is actually 
the least optimal. It is better to work along the client-server 
approach. This means that there is a central computer designated as a 
master of data and each client computer just talks to it and displays 
data locally. Alternatively, each computer can maintain its own copy of 
the text and sporadically synchronizes with others. But the algorithm 
for synchronization can be a real headache."

So if the text file is not the rigth way for handling multi users 
database, and that my next problem will be corruption by simultaneous 
writing access, may be it is more interesting to ask you what is the 
best way to manage databases under Revolution: What is a  client-server 
approach  ? Would SQL be usefull in that case? Heard speaking about 
substacks that can save data ( and didn't understand why the mainstack 
cannot). is it possible to easily manage Multi Users access to an 
external stack? Where can I learn about those, client  server, SQL, 
External stacks? Is it realistic to try it, if I tell you that I am 
already VERY busy...!?

      Many thanks for your help

Philippe Giraudet



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