[Zope] Cataloging AND (indexing OR meta data)

sean.upton@uniontrib.com sean.upton@uniontrib.com
Tue, 07 Aug 2001 09:57:36 -0700


Since ZCatalog objects are 'dumb' and don't have direct access to the
objects they have indexed, and it would be nice to have some of the data
from those objects for search results pages somehow, we need some way of
getting that data.  Metadata is essentially a cache of that data (or a copy,
that is) that is used for constructing result lists.  You should only put
fieldnames for properties containing summary data in the meta data tabs.

An alternative to using metadata in Zope 2.3+ is using Catalog.getObject()
which will return the object in each iteration; I currently do this in one
of my applications because I have had problems using metadata on some fields
(likely because I was doing it wrong).  There is a big performance penalty
for going about it this way, though, as you have to traverse the ODB to each
object to get data for each line in your result list.  Eventually, once I
get it working right, I will switch this over to using metadata instead,
which might increase re-indexing time, but increase result list performance
since I eliminate the need for getObject()...

Sean

-----Original Message-----
From: Peter Bengtsson [mailto:mail@peterbe.com]
Sent: Tuesday, August 07, 2001 9:18 AM
To: zope@zope.org
Subject: [Zope] Cataloging AND (indexing OR meta data)


I've got a bunch of objects that I catalog. I have added a few properties to
the Indexes which makes it possible for me now to search on these
properties.
Everything is jolly!

However, I honestly don't understand the Meta data tab. All I can
practically do there is add names of properties and that already works
spendid with the Indexes.
Anybody got a clear explaination for ZCatalog-dummy on this one?

PS. I read the Zope Book chapter on meta data but despite that I still
didn't get it.
Hopefully I've just lost a very important small piece of knowledge that is
needed.

Cheers, all



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