[Zope] ANN: ZCatalog 1.0.0 alpha

[Martijn Pieters]

At 15:52 28/06/99 , Michel Pelletier wrote:
> > * Right now, search results on multiple indexes are
> > intersected; if you
> > have a search term on the title and the body of a news item,
> > only objects
> > that have hits on both indexes are shown. This makes it practically
> > impossible to present one search field that will present the
> > user with
> > objects that have the search term in one of the indexes. I
> > would like to be
> > able to concatenate the results from different indexes.
> > intSet supports
> > this operation (union).
> >
>
>Oh man, I knew someone would open up the Query Language can of worms.

*smirk*

>Yep, your right, the catalog (like ZTables) takes only the intersection
>of a search.  Modifying the _indexedSearch() algorithm wouldn't be too
>hard, it's just *how* to modify it is the tricky part.  The ideal
>solution would be to create some sort of query language that web form
>could dynamicly build queries to, that way, you can design your querty
>rather smartly.  A nifty wizard could even be built to build complex web
>forms that you can then tweak for usability.  Brainstorm on this, and
>let me know what you come up with.

Hmm.. many searching interfaces that let you search on multiple fields 
(like Eudora 4.2) give you only the option to show objects that match any 
or all criteria. It would certainly solve my problem if we had this choice =).

Maybe ZCatalog should accept a special argument that specifies with a 
normal boolean search string how to join the results of the different 
indexes, something like:

         title and (summary or body)

which stands for the intersection of the search results on title and the 
union of the search results of summary and body. The parsing logic is 
already there.

This would allow for quite complex web interfaces, allowing for some nice 
datamining on ZCatalog instances. And it will allow me to do something like:

<dtml-call "REQUEST.set('title', search-string)">
<dtml-call "REQUEST.set('summary', search-string)">
<dtml-call "REQUEST.set('body', search-string)">

<dtml-call "REQUEST.set('results-join', 'title or summary or body')">

<dtml-in NewsCatalog size=20 start=query_start>
   .. displaying results ..
</dtml-in>

where results-join tells Catalog to use the union of title, summary and body.

Next question:

The tutorial talks about ZCatalog aware objects. How can I make a ZClass 
ZCatalog aware?

* Indexing an instance when adding is easy, as is updating the Catalog when 
editing but how does the deletion part work? Only when using a python base 
class?

* Is there a standard way of selecting the Catalog instance my newly 
created ZClass instance will use? Or should I just use:
<dtml-if "superValues('ZCatalog')">
   <dtml-if "_.len(superValues('ZCatalog')) > 1">
         <td><select name="catalog">
     <dtml-in "superValues('ZCatalog')">
         <option value=&dtml-id;><dtml-var title_and_id>
     </dtml-in>
     </select></td>
   <dtml-else>
     <dtml-in "superValues('ZCatalog')">
         <td><dtml-var title_and_id>
         <input type=hidden name=catalog value=&dtml-id;></td>
     </dtml-in>
   </dtml-if>
</dtml-if>
in the addForm?

--
Martijn Pieters, Web Developer
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