oodb philosophics ;) was: Re: [Zope-dev] Experiments with ORMapping

Cees de Groot cg@cdegroot.com
11 May 2001 23:36:15 +0200


Joachim Werner <joe@iuveno-net.de> said:
>[...]. E.g. how would
>you handle objects beloning to more than one container? In SQL this is easy
>(Just have a table that matches key pairs from the container table and the
>item table). And I don't know any good way of implementing "many-to-many"
>relations in object hierarchies. Let alone querying them efficiently.
>
Probably I'm daft because it is Friday night, but AFAIK ZODB and most OODB's
store an object only once, keyed by its object id. The rest is just references
through that oid, so objects that belong to more than one container can be
added to all these containers and n:m relations are implemented by having a
list of objects on both sides.