[Zope-dev] Re: [Zope3-dev] PROPOSAL: ZODB Relationships

[Oliver Bleutgen]

Phillip J. Eby wrote:
> At 11:07 PM 5/8/03 +0200, roche@upfrontsystems.co.za wrote:
> 
>> We finally have a proposal out for ZODB relationships. This proposal
>> presents an API for relationships, summarises ideas and contributions
>> from a lot of people and was fuelled by the recent discussions about
>> relationships on Zope3-dev and Zope-dev.
>>
>>     http://www.zope.org/Members/upfront/ZODBRelationships
>>
>> Your comments would be appreciated.
> 
> 
> Issues:
> 
> 1. "Global relationship repository" has no use cases, and smells like 
> trouble.  Why not just explicitly store the Relationship() somewhere?  
> After all, every RelationshipView will have a reference to it.  (For 
> ZODB4, a persistent module might be the natural place to put the 
> "official" reference to the Relationship(); for ZODB3, just hang them 
> off the root with suitably unique keys.)

First, I also think it should be possible to have more than one 
relationship. On argument for that is complexity of searches, another is 
virtual hosting and managability (import/export).
Additionaly, why should relationship repositories just hang down the 
root and have unique ids?
Maybe this is Zope3 related (which I don't know much about), but in 
zope2, it might be nice to use the acquisition machinery in discovering 
relationship storages.

Example: You want to create amazon2. Your products are stored in a 
folder hierachy.

books
   science
     philosopy
     mathematics
     CS
       OO
         Python
           Zope
           Twisted
           ...
         Java
           Websphere
           ...
         C++
         C#
       Producural
         C
         ...
       ...

etc.

You want to implement something like "People who were interested in 
<spam> also were interested in <eggs>" - but on every level of the 
hierachy, i.e. (Zope, Twisted) in the deepest, one above (Python, Java)
etc.

Now, wouldn't the most natural and economic way to do that to put a 
RelationshipStorage in every level?

Even if we consider the case that we'd like to store Relationships 
crossing hierachies, e.g. (Zope,Websphere), they'd be stored in the 
Relationship Storage which an ancestor of both of the objects to be 
stored, i.e. the one lying under OO.

cheers,
oliver