[Zope-CMF] DBObjects and CMF

[alan runyan]

> Is anyone out there using the DBObjects relational-to-object
> mapping product ( 
> http://www.zope.org/Members/srichter/Products/DBObjects )?
> Anyone using similar products? If so, how do they compare? I'm looking
> for some relational-to-object mapping code that will work nicely with
> my existing large-scale CMF instance.

I know Ben and Joel were talking about making Archetypes much nicer
for doing efficient O/R tasks.  But I think it would require funding 
for it
to move forward.  Archetypes has a highly inefficient way of doing it 
now.

You may also want to speak with Ian Bicking.  He wrote SQLObject which
is a simple O/R system.   He was talking about using Zope2 with it but
I am not sure how far he got.  We are using SQLObject with Zope3 with
great results.

> In particular, I'm looking for strategies people have used for
> presenting relational-style data as objects within CMF. CMF usage 
> presents
> some interesting challenges for this sort of data, particularly
> around workflow and change tracking, and I'd love to hear other 
> people's
> experiences. I've got some data feeds which are very relational,
> and storing the data directly in Zope seems to be a Bad Idea if
> I ever want to be able to modify the data in relational-style ways.

There are really two ways (that I know of):

   - On-the-fly traversal hooks.  I think something like 
CMFSubversionBrowser
   does stuff like this.  This is one level above the ZODB storage (I 
believe).

   - At the storage level - like apelib uses. I think this is really 
cool.

   - Having proxies in the ZODB that represent a SQL result.  I believe 
this is
   how DBObjects work.  And this is how it works in Archetypes at the 
moment.
   This is not a good approach for large scale systems.  I recommend 
against
   this approach.

You might want to check out a talk that Joel Burton did at the plone 
conference.

http://plone.org/events/conferences/1/video/

I do not believe anything he mentions is related to Plone specifically.

cheers,
~runyaga