[Zope] approach for persistent global links - is this good?

[Jens Wolk]

Salut everybody,

in a yellow pages ("zyp") product I need pointers or links between objects. 
For example I have categories and links to categories. It is necessary, that 
such a link to a category is still valid after having moved the category; 
this is why storing away the path isn't applicable.

As of now, Zope doesn't provide a global id one can work with.
(For a discussion about this issue and possible solutions in the future, see
http://dev.zope.org/Wikis/DevSite/Proposals/ObjectHub )

I found a solution which seems to work fine for me: each category gets an 
attribute called "zid". This zid is globally unique. (Based on a mechanism 
presented by alex.khan
http://dev.zope.org/Members/alex.khan/GlobalSystemId )

Storing a link is as easy as storing the zid of the linked category. However, 
the lookup of a linked category is done by a lookup in a ZCatalog with an 
appropriate field index. What do you think about this? This might not be such 
a good idea in terms of performance.

Your comments are very welcome

Jens Wolk