durusmail: durus-users: snag with btree.get(key)
snag with btree.get(key)
2005-07-07
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Schevo and moellus [was: Re: [Durus-users] snag with btree.get(key)]
2005-07-11
Re: Schevo and moellus [was: Re: [Durus-users] snag with btree.get(key)]
2005-07-13
2005-07-14
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2005-07-13
2005-07-07
snag with btree.get(key)
Mario Ruggier
2005-07-08
Hi Patrick,

nice idea, and thanks for suggesting it. I have not had the opportunity
to look closely at Schevo, i.e. use it, and I became aware of it only
when it was pointed out here around pycon time. I was already planning
to package a first release of moellus at that time.

Schevo is certainly interesting, and definitely more "ambitious"...
implementing rigourously the idea of an object model, plus accomodating
several back-ends, multi-editing tools, and so on. As you say, if I
were to take moellus that route, it would probably be a better idea to
take on Schevo instead. For me moellus was simply a means to simplify
usage of durus. And I have no intention of taking it much further. I
mention port to zodb below only in the spirit of "genericity", asking
what if? I really never had the intention to add zodb support to
moellus, and still don't... for using zodb there is a lot more
knowledge out there, than for using durus, and I would have looked at
how people use zodb first.

The driver behind moellus is the application I am working on... and the
features have evolved to meet those needs. A basic stumbler would
therefore be to port the application to another db layer. For new
project opportunities, Schevo is certainly on the my list of tools to
be considered.

I am not even familiar enough with Schevo to be able to compare
features... there is obviously some overlap, but i suspect they are
very different animals, and probably there are problems that may be
better addressed by one or the other. Just as there is good
justification for a db like Durus, when ZODB exists... or for Quixote
for that matter. If there is one problem with Python, it is this, that
it is so easy to implement things yourself! Anyhow, I am very attracted
by small light-weight designs, and my intention is to keep moellus as
light as possible.

But, really, I think it is silly, if flattering, to compare these two
frameworks...

Thanks for the links... weekend reading ;)

Cheers, mario



On Jul 8, 2005, at 2:50 PM, Patrick K. O'Brien wrote:
> Mario Ruggier wrote:
>>
>> I am using persistent instances **liberally** in btree keys, so a
>> straight porting to zodb would not work. However, the way my
>> persistent
>> items are defined, i can very easily get a (humanly descriptive)
>> string
>> tuple to identify each item.... but, that will add the overhead of
>> translating of instances to such immutable objects, on all the gets...
>> well, i guess it can always be another computed attribute ;)
>
> Perhaps you'd like to join forces in working on Schevo.  We've been
> doing a complete rewrite of Schevo from the ground up, specifically for
> Durus.  I believe we've already solved many of the issues you will be
> facing in trying to bring a relational model to Durus, since we've been
> working this issue for almost five years now.  In any case, our latest
> code can be found here:
>
> http://svn.orbtech.com/cgi-bin/schevo.cgi/browser/branches/rebel/
>
> Our Durus-specific code is here:
>
> http://svn.orbtech.com/cgi-bin/schevo.cgi/file/branches/rebel/schevo/
> database/duru.py
>
> --
> Patrick K. O'Brien
> Orbtech    http://www.orbtech.com
> Schevo     http://www.schevo.org
> Pypersyst  http://www.pypersyst.org
>

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