To: python-list@python.org
From: Dennis Lee Bieber <wlfraed@ix.netcom.com>
Subject: Re: PyQT app accessible over network?
Date: Fri, 22 Feb 2013 19:20:42 -0500
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On Fri, 22 Feb 2013 08:50:05 -0800, Monte Milanuk <memilanuk@gmail.com>
declaimed the following in gmane.comp.python.general:


> My concern is that using postgres or mysql for this would be akin to 
> using a sledgehammer to swat a fly, when sqlite could most likely handle 
> the load well enough (I think) since the handful of people doing data 
> entry would rarely (if ever) be trying to write to the same record. 
> That would be the whole point of having multiple people doing data entry 
> in this situation - each one handling a different competitors entry form 
> or submitted scores.
>

	Problem: SQLite3 (and M$ JET/Access) are considered "file server"
databases. Each instance of the program accessing the database is
directly opening the database file(s). While SQLite3 has a fairly
complex locking system, the normal locking is NOT "per record". Instead
it allows for multiple readers to be active at once; the first
connection/cursor to attempt to write anything will block any new
attempts to read, and will be blocked until all other active readers
exit (and none of those other readers can attempt to write). When there
are no other open readers, the writer can finish and commit changes.

> That is why I was looking at things in terms of having one central app 
> that handles the database, whether locally via sqlite or postgres or 
> whatever, but have the clients access go through that main application 
> in order to ensure that all they have is a limited set of CRUD abilities 
> for competitor registration and entering scores.
>
	At which point you've essentially written the conflict management
that a client/server system already provides.
-- 
	Wulfraed                 Dennis Lee Bieber         AF6VN
        wlfraed@ix.netcom.com    HTTP://wlfraed.home.netcom.com/