A Novel Framework to Measure the Degree of Difficulty on Keyword Query Routing

Abstract:- Spatial queries, such as range search and nearest neighbor retrieval, involve only conditions on objects geome-tric properties. A spatial database manages multidimensional objects(such as points, rectangles, etc.), and provides fast access to those objects based on different selection criteria.Keyword queries on databases provide easy access to data, but often suffer from low ranking quality, i.e., low precision and/or recall, as shown in recent benchmarks. It would be useful to identify queries that are likely to have low ranking quality to improve the user satisfaction. For instance, the system may sug-gest to the user alternative queries for such hard queries. In this paper, we analyze the characteristics of hard queries and propose a novel framework to measure the degree of difficulty for a keyword query over a database, considering both th