Query formulation from high-level concepts for relational databases

A new query formulation system based on a semantic graph model is presented. The graph provides a semantic model for the data in the database with user-defined relationships. The query formulator allows users to specify their requests and constraints in high-level concepts. The query candidates are formulated based on the user input by a graph search algorithm and ranked according to a probabilistic information measure. English-like query descriptions can also be provided for users to resolve ambiguity when multiple queries are formulated from a user input. For complex queries, we introduce an incremental approach, which assists users to achieve a complex query goal by formulating a series of simple queries. A prototype system with a multimodal interface using the high-level query formulation techniques has been implemented on top of a cooperative database system (CoBase) at UCLA.