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

[sean.upton at uniontrib.com]

I don't know much about MOF, but here is my understanding of what metatdata
would be required of associations and association "ends."

At the application level for content-management applications, here is a list
of metadata about a relationship (condensed and modified from:
http://mail.zope.org/pipermail/zope-cmf/2002-October/015801.html):

==> Direction
==> relationship type / model (i.e. "Has Part", "Is version of", "Requires")
	- each type usually has an inverse when you switch direction
		- i.e. "has part"/"is part of"
==> relationship label/keyword/name "Associated media", "Yesterday's
Coverage"
==> (optional) content type of referred to object (also a string/"label")
==> hubid, oid, path of content or some other identifier to each end
==> hold info: Is related object a dependency (Y/N)?

But we aren't talking about high-level relationship-management here.  It
would be nice to build on something that could provide the basic nuts and
bolts, though, to make such a thing possible in applications using a
lower-level framework.

Naming the association (Reference) with an attribute is a bare-minimum
requirement for being able to tack on higher-level stuff, like metadata
common to all instances of a reference with a given name.  Does an
AssociationEnd in MOF have the possibility for a name or label for each end
corresponding to a role in UML, or is MOF too 'strict' of a subset to allow
for this?

Each Reference or Association should have:
- Direction (i.e. referencedEnd, exposedEnd)
- A name / label
- Some notion of dependency???
- (optionally) a model type or label**

	** Model could be inferred from label via lookup table?

Each AssociationEnd should have:
- Name (role)
- Some binding or reference to the object the end is bound to*

Sean

-----Original Message-----
From: Roché Compaan [mailto:roche at upfrontsystems.co.za]
Sent: Saturday, May 10, 2003 2:55 AM
To: sean.upton at uniontrib.com
Cc: shane at zope.com; pje at telecommunity.com; zodb-dev at zope.org
Subject: Re: [ZODB-Dev] Re: [Zope3-dev] PROPOSAL: ZODB Relationships


On Fri, 09 May 2003 12:16:10 -0700
sean.upton at uniontrib.com wrote:

> The point is, when the relationship is created, we need to store a label
> about the relationship, or we have no way to infer the inverse.

Association in MOF has a name attribute so that should solve that
problem. Do you have any suggestion how we should handle metadata about
the association?


-- 
Roché Compaan
Upfront Systems                 http://www.upfrontsystems.co.za