From Revisiting the LCA-based Approach to a New Semantics-based Approach for XML Keyword Search

Most keyword search approaches for data-centric XML documents are based on the computation of Lowest Common Ancestors (LCA), such as SLCA and MLCA. In this paper, we show that the LCA is not always a correct search model for processing keyword queries over general XML data. In particular, when an XML database contains relationships among objects, which is quite common in practical data, LCA-based search may not be able to find desired answers for many keyword queries. We propose to use semantics instead of the structure of XML data to perform keyword search, and show that the semantics-based search can solve the problems of the LCA-based approach. To the best of our knowledge, this is the first work to point out serious problems of the LCA-based XML keyword search approach, and propose an approach to perform XML keyword search based on semantics rather than the hierarchical structure of XML data to address those problems.