Supporting range queries in XML keyword search

XML data is normally queried by rigorous structured query languages, e.g., XPath, XQuery, etc. In recent years keyword search has become more and more popular because it provides a more user-friendly way to explore data. Keyword search on XML data has also been a hot research issue recently. So far none of the existing XML keyword search methods has considered range queries. In this paper we point out that supporting range queries in XML keyword search is beneficial and non-trivial to the user, especially in the case of querying business semi-structured data, where numerals (like stock price, product quantity, market share percentage, etc.) could be the main part of the data. Actually existing XML keyword search methods do not support range queries at two levels: keyword query syntax level and keyword search method level. To support range queries in XML keyword search: (1) we enrich the current XML keyword query syntax to let the user make range specification; (2) we then extend existing XML keyword search methods by proposing a new index to support both range match and point match. The new index is transparent to existing XML keyword search methods. It can seamlessly work with them and well support range queries in XML keyword search.