[Tutor] ways to sync databases with Python and SQLite?

[Alan Gauld]

"Che M" <pine508 at hotmail.com> wrote

> I get the sense that Alan's idea of a log file to tell each DB 
> how to change to keep current would work.  What 
> are the "very hard" aspects of that?  

The main issues are around conflicting edits. If both are 
just adding records its OK but if one deletes a record and 
the other subsequently updates the same record things 
get a tad confusing!

You need to merge the two lots of changes in time 
order then remove any rogue deletes and manage 
parallel updates. 

If you only allow additions to be sync'd then its all 
a lot easier. Or you can only apply the last update
(even if for different fields). Several options to simplify 
things. But too simple ultimately means inconsistent 
records...

-- 
Alan Gauld
Author of the Learn to Program web site
http://www.freenetpages.co.uk/hp/alan.gauld