Online users are constantly seeking experiences, such as a hotel
with clean rooms and a lively bar, or a restaurant for a romantic
rendezvous. However, e-commerce search engines only support
queries involving objective attributes such as location, price, and
cuisine, and any experiential data is relegated to text reviews.
In order to support experiential queries, a database system needs
to model subjective data. Users should be able to pose queries that
specify subjective experiences using their own words, in addition to
conditions on the usual objective attributes. This paper introduces
OpineDB, a subjective database system that addresses these challenges. We introduce a data model for subjective databases. We describe how OpineDB translates subjective queries against the subjective database schema, which is done by matching the user query
phrases to the underlying schema. We also show how the experiential conditions specified by the user can be combined and the results
aggregated and ranked. We demonstrate that subjective databases
satisfy user needs more effectively and accurately than alternative
techniques through experiments with real data of hotel and restaurant reviews.