Retune: Retrieving and Materializing Tuple Units for Effective Keyword Search over Relational Databases

The existing approaches of keyword search over relational databases always identify the relationships between tuples on the fly, which are rather inefficient as such relational relationships are very rich in the underlying databases. Alternatively, this paper proposes an alternative way by retrieving and materializing tuple units for facilitating the online processing of keyword search. We first propose a novel concept of tuple units, which are composed of the relevant tuples connected by the primary-foreign-key relationships. We then demonstrate how to generate and materialize the tuple units, and the technique for generating the tuple units can be done by issuing SQL statements and thus can be performed directly on the underlying RDBMS without modification to the database engine. Finally, we examine the techniques of indexing and ranking to improve the search efficiency and search quality. We have implemented our method and the experimental results show that our approach achieves much better search performance, and outperforms the alternative literatures significantly.