Query by templates: a generalized approach for visual query formulation for text dominated databases

The WWW has a great potential of evolving into a globally distributed digital document library. The primary use of such a library is to retrieve information quickly and easily. Because of the size of these libraries, simple keyword searches often result in too many matches. More complex searches involving boolean expressions are difficult to formulate and understand. This paper describes QBT (Query By Templates), a visual method for formulating queries for structured document databases modeled with SGML. Based on Zloof's QBE (Query By Example), this method incorporates the structure of the documents for composing powerful queries. The goal of this technique is to design an interface for querying structured documents without prior knowledge of the internal structure. This paper describes the rationale behind QBT, illustrates the query formulation principles using QBT, and describes results obtained from a usability analysis on a prototype implementation of QBT on the Web using the Java/sup TM/ programming language.