My question is inspired by this articlehttp://www.dominoblog.com/dominoblog/dblog.nsf/dx/faq-on-db2-integration.
I tried to create query view by this steps
http://publib-b.boulder.ibm.com/lotus/c2359850.nsf/f4b82fbb75e942a6852566ac0037f284/993249781ece01918525731b0048ba43?OpenDocument but what is “Query Window”?
Is DB2 necessary for this amazing feature?
Subject: Yes, DB2 is necessary…
Specifically, you have to have the Notes databases involved stored in NSFDB2 format, as a first step.
Subject: performance issue?
Thanks for response. And what about performance? I’m afraid: client - Domino - DB server - Domino - client… :(Is there other way how rich relational behaviour in LN database?
Subject: Performance is great for filtered views
The data is stored in db2 and accessed in a notes view. The view can combine db2 data from different tables (which could be different notes forms).
For us, view that are filtered (like notes search) or combined data (which you can’t do in notes) are faster.
Check here: http://www.kalechi.com/comments.nsf/dx/db2-and-Domino
and the lotus domino web development best practice wiki for more info.
Subject: 
thanks for answer and inspiration