Keeping python code and database in sync

[dieter]

"Frank Millman" <frank at chagford.com> writes:
> ...
> It is a simple matter to write a program that updates the database 
> automatically. The question is, what should trigger such an update? My first 
> thought is to use a version number - store a version number in the working 
> directory, and have a matching number in the code. If someone downloads the 
> latest version, the numbers will no longer match, and I can run the upgrade 
> program.
>
> The problem with that is that version numbers are usually reserved for 
> tagged releases, but this could happen as the result of any commit in the 
> current development cycle.

I use "data model version number"s for this. They identify the
data model version and are idenpendent of any program version number.
Such a version number is changed whenever the data model changes
(and there is the need for a model upgrade).