Re: bitmap join index error

JusungYang_at_yahoo.com (Jusung Yang) wrote in message news:<130ba93a.0307171055.29953f96_at_posting.google.com>...
> ageev_at_mail.cir.ru (Misha Ageev) wrote in message news:<877c3c6c.0307170517.6841e6e0_at_posting.google.com>...
> > Such index allow to quickly run queries like
> > (
> > (SELECT feat_id FROM ma14_doc_feats dfi WHERE doc_id=1
> > INTERSECT
> > SELECT feat_id FROM ma14_doc_feats dfi WHERE doc_id=2
> > )
> > MINUS
> > SELECT feat_id FROM ma14_doc_feats dfi WHERE doc_id=3
> > )
> > UNION
> > SELECT feat_id FROM ma14_doc_feats dfi WHERE doc_id=4
> >
>
> Hmm... You sure this is the query you want?

Yes. I develop a text classification system where each category is represented by a boolean formulae. I need to select all documents that have a given stucture of features, and in reverse all features that have a given stucture of documents.

This leads to a boolean queries like those I mentioned.

Currently I use B+tree indexes and I sure the correct bitmap indexes can speed up the computation.

Misha. Received on Fri Jul 18 2003 - 06:45:00 CDT