HVQS: The hierarchical visual query system for databases

This work describes the design and implementation of hierarchical visual query system (HVQS). It is a user interface for querying and browsing databases in a hierarchical database schema. HVQS enables users to use a hierarchical visual query, i.e. they can visually formulate a query and watch the query results on a few higher layers of database schema. This simplifies the query, reduces the failure rate, conserves query time, allows users to work on a database schema with wider scope, and helps users understand database content and focus on meaningful data using a top-down method. This work first gives an overview of the hierarchical visual query, and then describes the prototype of HVQS, defines a hierarchical graph for representing hierarchical database schema, and discusses the Query Manager and Visual Interface Manager of HVQS. Also described herein is the expressive power and semantics of HVQS query. Finally, a evaluation report of an experiment is given to demonstrate that HVQS improves the query success rate and facilitates users in query formulation. (C) 2000 Academic Press.