[Zope-dev] Hey Chris, question for you

Chris McDonough chrism@digicool.com
Tue, 26 Jun 2001 21:17:22 -0400


Hi casey,

Changes were recently made to Field/Keyword Indexes so that they will
store empty items.  An equivalent change could be made to TextIndexes...
we'd need to think about that a bit.

But for your purposes, you might want to start out attempting to write
your operator implementation using Field and Keyword indexes...

- C


Michel Pelletier wrote:
> 
> On Tue, 26 Jun 2001, Casey Duncan wrote:
> 
> > Ok, I was able to get it to work by instantiating a IISet around
> > _unindex.keys() and passing that to difference (Thanks!), however, I
> > notice an interesting side effect. Let's say you have a TextIndex on
> > title and you do the following query:
> >
> > title != 'foo*'
> >
> > Which to me means: "all cataloged objects whose title do not match the
> > substring 'foo*'"
> >
> > However, this is not what you get exactly, instead you get:
> >
> > "all cataloged objects that have a non-empty title that does not match
> > the substring 'foo*'"
> >
> > Because from what I am seeing, objects with empty (or no) titles are not
> > included in the index *at all*. So the set of "all objects" does not
> > include ones without titles. I could fix this by making all objects be
> > instead "All objects in the catalog" (via catalog.data.keys()) instead
> > of "all objects in the index", but I wanted to see if anyone had
> > additional thoughts about this.
> 
> Hmm the reason for the current behavior was optimization by saving space
> not indexing empty values.  The problem with your latter aproach is that
> "all objects in the catalog" may include object that don't have a title
> attribute at all.
> 
> I'm not against indexing empty values though.
> 
> -Michel
> 
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