[ZPatterns] Revisiting an old question: Reusable ZPatterns applications

[Steve Spicklemire]

Hmm.... what if the actual persistent storage were separated from the 
Rack? Steve.. didn't you cook up and External storage for Racks at some 
point? This way the stored objects could be exported/imported using the 
"normal" approach and the Rack (and it's PlugIns) could be updated 
separately.

-steve

On Friday, September 14, 2001, at 03:49 AM, Steve Alexander wrote:

> I'd just composed a reply to this, when we had a 2 hour power-cut :-/
>
> Here goes my second try.
>
> Itai Tavor wrote:
> >
>
>> Second, and this is where the whole thing becomes quite impossible, 
>> there's the problem of upgrading the application, for bug fixes or 
>> feature changes. With a normal app, you install a new copy, refresh 
>> the product, and you got the new application working with all your 
>> existing data.
>
>
> My procedure for this goes like this:
>
> 1: Export data from Racks to an xml file on the filesystem
> 2: Install new Data.fs / Zope+Python+Data.fs+External Methods etc.
> 3: Reimport data from Racks
> 4: Update Catalogs (in dependency order) from the ids in the imported 
> data
>
> Note that when I say "export as xml", I mean to a domain-specific xml 
> DTD using an external method.
>
> The advantage of this is that it is easy to migrate the application 
> between very different schemas. I needed to do this when I converted an 
> application from Specialists+Racks and Customizers to just 
> Specialists+Racks.
>
> --
> Steve Alexander
> Software Engineer
> Cat-Box limited
>
>
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