[Zope] ZODB vs SQL, ZTables

[Michel Pelletier]

> -----Original Message-----
> From: Jordan B. Baker [mailto:jbb@spyderlab.com]
> Sent: Monday, June 07, 1999 3:01 PM
> To: zope@zope.org
> Subject: RE: [Zope] ZODB vs SQL, ZTables
> 
> 
> On Mon, 7 Jun 1999, Michel Pelletier wrote:
> 
> > > 1) Would I be re-inventing the wheel here?  Can ZTables 
> instantiate
> > > ZClasses?  The reason I like the ZClasses is because I'd like 
> > > to write my
> > > business logic in Python.  I suppose I could do this with External
> > > methods.
> > 
> > ZTables return an result 'object' called a 'brain'.  This object is
> > instanciated on the fly when you make queries.  If you 
> define your own
> > type of brain, then you can have your own types of objects. 
>  I don't see
> > any reason why this object couldn't be a ZClass, but 
> currently there is
> > no mechanism to hook the two together through the ZClass, 
> there would
> > have to be some python involved.
> 
> This is pretty intriguing.  I need to consider the cost/benefits.
> 
> One thing I don't like about this is that (I assume) you 
> can't change the
> data in the ZTable simply by assigning attributes as you could if each
> piece of data was stored as objects.
> 

Correct.  The 'brains' aren't persistent or connected to the ZTable in
any way, it would be, of course, possible to write methods for the
brains class that manipulated the ZTable data, as you suggest below.

> Either way it would be fairly easy to write getter/setter methods that
> would use a ZTables API to update the records.  I assume this 
> would work
> anyway.
> 
<snip>
> 
> Well, I'd certainly be willing to provide feedback on the 
> documentation as
> this would give me an idea of how it works at a lower level.  
> And it means
> I could start protyping some of my ideas today instead of 
> waiting for the
> internal QA of the Catalog to move along.

Currently it's just a UML diagram and some documentation associated with
it.  In the spirit of releasing UML as our documentation format, I will
probably be releasing the ZopeIndexing diagram soon.  This is the
'documentation'.

<snip>
> 
> If there is any alpha testing going with it I'd be willing to run it
> through its paces.  Otherwise roughly when do you think 
> Catalog will be
> available in some form?
> 

We will be discussing that today.

-Michel