1. Users play no role in traditional database queries. The results returned by DB are 100% correct wrt the query.
2. IR query Challenges:
(a) IR doesn't understand NLP,
(b) user is aware of this fact.
(c) User is not sure what s/he is looking for.
3.Due to above IR queries are usually imprecise, under-constrained & imposed. True relevance to the IR queries is imposed by User.
-Rashmi Dubey
