[Zope-dev] more on keyword indexes

[Steve Alexander]

Hi Josh,

I use KeywordIndexes a lot.

Just for kicks, I implemented what you describe below in Zope2.3 grabbed 
fresh from CVS just now.

I used DTML Documents for the objects to catalog, and I added a lines 
property called KW to each one.

I queried the catalog using syntax like
   <dtml-in "Catalog(KW=['one', 'two'])">
or
   <dtml-in "Catalog(KW='purple')">


Josh Zeidner wrote:

> Hello,
> 
>   I did a little more investigiation into the problem, and couldnt really
> find any documentation anywhere on what the actual semantics are of keywords
> and how they are queried.  For instance:
> 
>   I have three classes and each has an keyword index named KW:
> 
>   ObjectOne:    KW = ['one','blue','furry']
>   ObjectTwo:    KW = ['two','flying','purple']
>   ObjectThree:  KW = ['three','one-eyed','purple']
> 
>   If I were to query the ZCatalog with the following set of words:
> ['purple'] I would expect to get:
> 
>     ObjectTwo
>     ObjectThree

Yes, that's what you get.

>   Right?  If I query the database with ['one','two'] ( if this type of thing
> is at all possible ), I get :
> 
>     ObjectOne
>     ObjectTwo

Yes, that's what you get.

>   This seems like the obvious result: BUT: it depends if you want a AND/OR
> type search.  

It is an OR search.

> I could also expect to get nothing( if its an AND type search
> because no records match 'one' and 'two' ).  Here is better example, what if
> I queried: ['purple','one-eyed'].  Would I be expecting only ObjectThree or
> [ ObjectThree, ObjectTwo ] ( because they both match the keyword purple( a
> logical set-intersection ) ).

You get ObjectTwo and ObjectThree.


>   Also I found the keyword indexes to have some more obvious bugs.  If I
> only used one keyword for the matching critiria,  for instance if I used
> 'purple' , I would only get ObjectTwo.

I get ObjectTwo and ObjectThree, as I'd expect.


> Is anyone else using keyword
> indexes?  In what way are you using them?

All sorts of things. One useful use is to limit a query on a SiteIndex 
type of catalog to just a sub-tree of your site.

See my message to zope-dev on October:

   http://lists.zope.org/pipermail/zope-dev/2000-October/007535.html


--
Steve Alexander
Software Engineer
Cat-Box limited
http://www.cat-box.net